Move the BootstrapperApplication out of proc

54 files changed, 8492 insertions, 2292 deletions

diff --git a/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperEngine.h b/src/api/burn/WixToolset.BootstrapperCore.Native/inc/baenginetypes.h
index 96302bd1..7af41d97 100644
--- a/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperEngine.h
+++ b/src/api/burn/WixToolset.BootstrapperCore.Native/inc/baenginetypes.h
@@ -86,6 +86,7 @@ enum BOOTSTRAPPER_UPDATE_HASH_TYPE
 
 enum BOOTSTRAPPER_ENGINE_MESSAGE
 {
+    BOOTSTRAPPER_ENGINE_MESSAGE_UNKNOWN,
     BOOTSTRAPPER_ENGINE_MESSAGE_GETPACKAGECOUNT,
     BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLENUMERIC,
     BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLESTRING,
@@ -112,159 +113,161 @@ enum BOOTSTRAPPER_ENGINE_MESSAGE
     BOOTSTRAPPER_ENGINE_MESSAGE_SETUPDATESOURCE,
     BOOTSTRAPPER_ENGINE_MESSAGE_COMPAREVERSIONS,
     BOOTSTRAPPER_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE,
+
+    BOOTSTRAPPER_APPLICATION_MESSAGE_LAST = 65535
 };
 
 typedef struct _BAENGINE_APPLY_ARGS
 {
-    DWORD cbSize;
-    HWND hwndParent;
+    DWORD dwApiVersion;
+    DWORD64 hwndParent;
 } BAENGINE_APPLY_ARGS;
 
 typedef struct _BAENGINE_APPLY_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_APPLY_RESULTS;
 
 typedef struct _BAENGINE_CLOSESPLASHSCREEN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_CLOSESPLASHSCREEN_ARGS;
 
 typedef struct _BAENGINE_CLOSESPLASHSCREEN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_CLOSESPLASHSCREEN_RESULTS;
 
 typedef struct _BAENGINE_COMPAREVERSIONS_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzVersion1;
     LPCWSTR wzVersion2;
 } BAENGINE_COMPAREVERSIONS_ARGS;
 
 typedef struct _BAENGINE_COMPAREVERSIONS_RESULTS
 {
-    DWORD cbSize;
-    int nResult;
+    DWORD dwApiVersion;
+    INT32 nResult;
 } BAENGINE_COMPAREVERSIONS_RESULTS;
 
 typedef struct _BAENGINE_DETECT_ARGS
 {
-    DWORD cbSize;
-    HWND hwndParent;
+    DWORD dwApiVersion;
+    DWORD64 hwndParent;
 } BAENGINE_DETECT_ARGS;
 
 typedef struct _BAENGINE_DETECT_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_DETECT_RESULTS;
 
 typedef struct _BAENGINE_ELEVATE_ARGS
 {
-    DWORD cbSize;
-    HWND hwndParent;
+    DWORD dwApiVersion;
+    DWORD64 hwndParent;
 } BAENGINE_ELEVATE_ARGS;
 
 typedef struct _BAENGINE_ELEVATE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_ELEVATE_RESULTS;
 
 typedef struct _BAENGINE_ESCAPESTRING_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzIn;
 } BAENGINE_ESCAPESTRING_ARGS;
 
 typedef struct _BAENGINE_ESCAPESTRING_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPWSTR wzOut;
     // Should be initialized to the size of wzOut.
-    SIZE_T cchOut;
+    DWORD cchOut;
 } BAENGINE_ESCAPESTRING_RESULTS;
 
 typedef struct _BAENGINE_EVALUATECONDITION_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzCondition;
 } BAENGINE_EVALUATECONDITION_ARGS;
 
 typedef struct _BAENGINE_EVALUATECONDITION_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL f;
 } BAENGINE_EVALUATECONDITION_RESULTS;
 
 typedef struct _BAENGINE_FORMATSTRING_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzIn;
 } BAENGINE_FORMATSTRING_ARGS;
 
 typedef struct _BAENGINE_FORMATSTRING_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPWSTR wzOut;
     // Should be initialized to the size of wzOut.
-    SIZE_T cchOut;
+    DWORD cchOut;
 } BAENGINE_FORMATSTRING_RESULTS;
 
 typedef struct _BAENGINE_GETPACKAGECOUNT_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_GETPACKAGECOUNT_ARGS;
 
 typedef struct _BAENGINE_GETPACKAGECOUNT_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD cPackages;
 } BAENGINE_GETPACKAGECOUNT_RESULTS;
 
 typedef struct _BAENGINE_GETVARIABLENUMERIC_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzVariable;
 } BAENGINE_GETVARIABLENUMERIC_ARGS;
 
 typedef struct _BAENGINE_GETVARIABLENUMERIC_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LONGLONG llValue;
 } BAENGINE_GETVARIABLENUMERIC_RESULTS;
 
 typedef struct _BAENGINE_GETVARIABLESTRING_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzVariable;
 } BAENGINE_GETVARIABLESTRING_ARGS;
 
 typedef struct _BAENGINE_GETVARIABLESTRING_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPWSTR wzValue;
     // Should be initialized to the size of wzValue.
-    SIZE_T cchValue;
+    DWORD cchValue;
 } BAENGINE_GETVARIABLESTRING_RESULTS;
 
 typedef struct _BAENGINE_GETVARIABLEVERSION_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzVariable;
 } BAENGINE_GETVARIABLEVERSION_ARGS;
 
 typedef struct _BAENGINE_GETVARIABLEVERSION_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPWSTR wzValue;
     // Should be initialized to the size of wzValue.
-    SIZE_T cchValue;
+    DWORD cchValue;
 } BAENGINE_GETVARIABLEVERSION_RESULTS;
 
 typedef struct _BAENGINE_LAUNCHAPPROVEDEXE_ARGS
 {
-    DWORD cbSize;
-    HWND hwndParent;
+    DWORD dwApiVersion;
+    DWORD64 hwndParent;
     LPCWSTR wzApprovedExeForElevationId;
     LPCWSTR wzArguments;
     DWORD dwWaitForInputIdleTimeout;
@@ -272,57 +275,58 @@ typedef struct _BAENGINE_LAUNCHAPPROVEDEXE_ARGS
 
 typedef struct _BAENGINE_LAUNCHAPPROVEDEXE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_LAUNCHAPPROVEDEXE_RESULTS;
 
 typedef struct _BAENGINE_SETUPDATESOURCE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzUrl;
+    LPCWSTR wzAuthorizationHeader;
 } BAENGINE_SETUPDATESOURCE_ARGS;
 
 typedef struct _BAENGINE_SETUPDATESOURCE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_SETUPDATESOURCE_RESULTS;
 
 typedef struct _BAENGINE_LOG_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_LOG_LEVEL level;
     LPCWSTR wzMessage;
 } BAENGINE_LOG_ARGS;
 
 typedef struct _BAENGINE_LOG_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_LOG_RESULTS;
 
 typedef struct _BAENGINE_PLAN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_ACTION action;
 } BAENGINE_PLAN_ARGS;
 
 typedef struct _BAENGINE_PLAN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_PLAN_RESULTS;
 
 typedef struct _BAENGINE_QUIT_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD dwExitCode;
 } BAENGINE_QUIT_ARGS;
 
 typedef struct _BAENGINE_QUIT_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_QUIT_RESULTS;
 
 typedef struct _BAENGINE_SENDEMBEDDEDERROR_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD dwErrorCode;
     LPCWSTR wzMessage;
     DWORD dwUIHint;
@@ -330,41 +334,42 @@ typedef struct _BAENGINE_SENDEMBEDDEDERROR_ARGS
 
 typedef struct _BAENGINE_SENDEMBEDDEDERROR_RESULTS
 {
-    DWORD cbSize;
-    int nResult;
+    DWORD dwApiVersion;
+    INT32 nResult;
 } BAENGINE_SENDEMBEDDEDERROR_RESULTS;
 
 typedef struct _BAENGINE_SENDEMBEDDEDPROGRESS_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD dwProgressPercentage;
     DWORD dwOverallProgressPercentage;
 } BAENGINE_SENDEMBEDDEDPROGRESS_ARGS;
 
 typedef struct _BAENGINE_SENDEMBEDDEDPROGRESS_RESULTS
 {
-    DWORD cbSize;
-    int nResult;
+    DWORD dwApiVersion;
+    INT32 nResult;
 } BAENGINE_SENDEMBEDDEDPROGRESS_RESULTS;
 
 typedef struct _BAENGINE_SETDOWNLOADSOURCE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     LPCWSTR wzUrl;
     LPCWSTR wzUser;
     LPCWSTR wzPassword;
+    LPCWSTR wzAuthorizationHeader;
 } BAENGINE_SETDOWNLOADSOURCE_ARGS;
 
 typedef struct _BAENGINE_SETDOWNLOADSOURCE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_SETDOWNLOADSOURCE_RESULTS;
 
 typedef struct _BAENGINE_SETLOCALSOURCE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     LPCWSTR wzPath;
@@ -372,39 +377,40 @@ typedef struct _BAENGINE_SETLOCALSOURCE_ARGS
 
 typedef struct _BAENGINE_SETLOCALSOURCE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_SETLOCALSOURCE_RESULTS;
 
 typedef struct _BAENGINE_SETUPDATE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzLocalSource;
     LPCWSTR wzDownloadSource;
     DWORD64 qwSize;
     BOOTSTRAPPER_UPDATE_HASH_TYPE hashType;
     LPCWSTR wzHash;
+    LPCWSTR wzUpdatePackageId;
 } BAENGINE_SETUPDATE_ARGS;
 
 typedef struct _BAENGINE_SETUPDATE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_SETUPDATE_RESULTS;
 
 typedef struct _BAENGINE_SETVARIABLENUMERIC_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzVariable;
     LONGLONG llValue;
 } BAENGINE_SETVARIABLENUMERIC_ARGS;
 
 typedef struct _BAENGINE_SETVARIABLENUMERIC_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_SETVARIABLENUMERIC_RESULTS;
 
 typedef struct _BAENGINE_SETVARIABLESTRING_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzVariable;
     LPCWSTR wzValue;
     BOOL fFormatted;
@@ -412,42 +418,42 @@ typedef struct _BAENGINE_SETVARIABLESTRING_ARGS
 
 typedef struct _BAENGINE_SETVARIABLESTRING_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_SETVARIABLESTRING_RESULTS;
 
 typedef struct _BAENGINE_SETVARIABLEVERSION_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzVariable;
     LPCWSTR wzValue;
 } BAENGINE_SETVARIABLEVERSION_ARGS;
 
 typedef struct _BAENGINE_SETVARIABLEVERSION_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 } BAENGINE_SETVARIABLEVERSION_RESULTS;
 
 typedef struct _BAENGINE_GETRELATEDBUNDLEVARIABLE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzBundleId;
     LPCWSTR wzVariable;
 } BAENGINE_GETRELATEDBUNDLEVARIABLE_ARGS;
 
 typedef struct _BAENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPWSTR wzValue;
     // Should be initialized to the size of wzValue.
-    SIZE_T cchValue;
+    DWORD cchValue;
 } BAENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS;
 
-extern "C" typedef HRESULT(WINAPI *PFN_BOOTSTRAPPER_ENGINE_PROC)(
-    __in BOOTSTRAPPER_ENGINE_MESSAGE message,
-    __in const LPVOID pvArgs,
-    __inout LPVOID pvResults,
-    __in_opt LPVOID pvContext
-    );
+// extern "C" typedef HRESULT(WINAPI *PFN_BOOTSTRAPPER_ENGINE_PROC)(
+//     __in BOOTSTRAPPER_ENGINE_MESSAGE message,
+//     __in const LPVOID pvArgs,
+//     __inout LPVOID pvResults,
+//     __in_opt LPVOID pvContext
+//     );
 
 #if defined(__cplusplus)
 }
diff --git a/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h b/src/api/burn/WixToolset.BootstrapperCore.Native/inc/batypes.h
index 2633a9c2..0116364c 100644
--- a/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h
+++ b/src/api/burn/WixToolset.BootstrapperCore.Native/inc/batypes.h
@@ -2,6 +2,10 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
 
+const LPCWSTR BOOTSTRAPPER_APPLICATION_COMMANDLINE_SWITCH_API_VERSION = L"burn.ba.apiver";
+const LPCWSTR BOOTSTRAPPER_APPLICATION_COMMANDLINE_SWITCH_PIPE_NAME = L"burn.ba.pipe";
+const DWORD WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION = 5;
+
 enum BOOTSTRAPPER_DISPLAY
 {
     BOOTSTRAPPER_DISPLAY_UNKNOWN,
@@ -143,27 +147,30 @@ enum BOOTSTRAPPER_MSI_FILE_VERSIONING
 
 enum BOOTSTRAPPER_APPLICATION_MESSAGE
 {
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTBEGIN,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPLETE,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANBEGIN,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPLETE,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_UNKNOWN = 65536,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONCREATE,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDESTROY,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONSTARTUP,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONSHUTDOWN,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTBEGIN,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPLETE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTFORWARDCOMPATIBLEBUNDLE,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTMSIFEATURE,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGEBEGIN,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGECOMPLETE,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPATCHTARGET,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLE,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDMSIPACKAGE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATEBEGIN,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATECOMPLETE,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLE,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGEBEGIN,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDMSIPACKAGE,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPATCHTARGET,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTMSIFEATURE,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGECOMPLETE,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLE,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGEBEGIN,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPATCHTARGET,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANBEGIN,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPLETE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANMSIFEATURE,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGEBEGIN,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGECOMPLETE,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPATCHTARGET,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYBEGIN,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATEBEGIN,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATECOMPLETE,
@@ -215,8 +222,6 @@ enum BOOTSTRAPPER_APPLICATION_MESSAGE
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTCOMPLETE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTPROGRESS,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANROLLBACKBOUNDARY,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONSETUPDATEBEGIN,
-    BOOTSTRAPPER_APPLICATION_MESSAGE_ONSETUPDATECOMPLETE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPATIBLEMSIPACKAGE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGEBEGIN,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE,
@@ -345,7 +350,7 @@ struct BOOTSTRAPPER_COMMAND
     BOOTSTRAPPER_DISPLAY display;
 
     LPWSTR wzCommandLine;
-    int nCmdShow;
+    INT32 nCmdShow;
 
     BOOTSTRAPPER_RESUME_TYPE resumeType;
     HWND hwndSplashScreen;
@@ -361,19 +366,19 @@ struct BOOTSTRAPPER_COMMAND
 
 struct BA_ONAPPLYBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD dwPhaseCount;
 };
 
 struct BA_ONAPPLYBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONAPPLYCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
     // Indicates whether any package required a reboot or initiated the reboot already.
     BOOTSTRAPPER_APPLY_RESTART restart;
@@ -382,49 +387,49 @@ struct BA_ONAPPLYCOMPLETE_ARGS
 
 struct BA_ONAPPLYCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_APPLYCOMPLETE_ACTION action;
 };
 
 struct BA_ONAPPLYDOWNGRADE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrRecommended;
 };
 
 struct BA_ONAPPLYDOWNGRADE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONBEGINMSITRANSACTIONBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzTransactionId;
 };
 
 struct BA_ONBEGINMSITRANSACTIONBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONBEGINMSITRANSACTIONCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzTransactionId;
     HRESULT hrStatus;
 };
 
 struct BA_ONBEGINMSITRANSACTIONCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONCACHEACQUIREBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     LPCWSTR wzSource;
@@ -435,14 +440,14 @@ struct BA_ONCACHEACQUIREBEGIN_ARGS
 
 struct BA_ONCACHEACQUIREBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOTSTRAPPER_CACHE_OPERATION action;
 };
 
 struct BA_ONCACHEACQUIRECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     HRESULT hrStatus;
@@ -451,13 +456,13 @@ struct BA_ONCACHEACQUIRECOMPLETE_ARGS
 
 struct BA_ONCACHEACQUIRECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_CACHEACQUIRECOMPLETE_ACTION action;
 };
 
 struct BA_ONCACHEACQUIREPROGRESS_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     DWORD64 dw64Progress;
@@ -467,13 +472,13 @@ struct BA_ONCACHEACQUIREPROGRESS_ARGS
 
 struct BA_ONCACHEACQUIREPROGRESS_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCACHEACQUIRERESOLVING_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     LPCWSTR* rgSearchPaths;
@@ -487,7 +492,7 @@ struct BA_ONCACHEACQUIRERESOLVING_ARGS
 
 struct BA_ONCACHEACQUIRERESOLVING_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD dwChosenSearchPath;
     BOOTSTRAPPER_CACHE_RESOLVE_OPERATION action;
     BOOL fCancel;
@@ -495,42 +500,42 @@ struct BA_ONCACHEACQUIRERESOLVING_RESULTS
 
 struct BA_ONCACHEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONCACHEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCACHECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONCACHECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
 };
 
 struct BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     HRESULT hrStatus;
@@ -538,12 +543,12 @@ struct BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_ARGS
 
 struct BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     DWORD64 dw64Progress;
@@ -553,13 +558,13 @@ struct BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_ARGS
 
 struct BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCACHEPACKAGEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     DWORD cCachePayloads;
     DWORD64 dw64PackageCacheSize;
@@ -569,13 +574,13 @@ struct BA_ONCACHEPACKAGEBEGIN_ARGS
 
 struct BA_ONCACHEPACKAGEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCACHEPACKAGECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     HRESULT hrStatus;
     BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION recommendation;
@@ -583,13 +588,13 @@ struct BA_ONCACHEPACKAGECOMPLETE_ARGS
 
 struct BA_ONCACHEPACKAGECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION action;
 };
 
 struct BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     HRESULT hrStatus;
     BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION recommendation;
@@ -597,26 +602,26 @@ struct BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_ARGS
 
 struct BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION action;
 };
 
 struct BA_ONCACHEPAYLOADEXTRACTBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzContainerId;
     LPCWSTR wzPayloadId;
 };
 
 struct BA_ONCACHEPAYLOADEXTRACTBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCACHEPAYLOADEXTRACTCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzContainerId;
     LPCWSTR wzPayloadId;
     HRESULT hrStatus;
@@ -624,12 +629,12 @@ struct BA_ONCACHEPAYLOADEXTRACTCOMPLETE_ARGS
 
 struct BA_ONCACHEPAYLOADEXTRACTCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONCACHEPAYLOADEXTRACTPROGRESS_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzContainerId;
     LPCWSTR wzPayloadId;
     DWORD64 dw64Progress;
@@ -639,26 +644,26 @@ struct BA_ONCACHEPAYLOADEXTRACTPROGRESS_ARGS
 
 struct BA_ONCACHEPAYLOADEXTRACTPROGRESS_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCACHEVERIFYBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
 };
 
 struct BA_ONCACHEVERIFYBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCACHEVERIFYCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     HRESULT hrStatus;
@@ -667,13 +672,13 @@ struct BA_ONCACHEVERIFYCOMPLETE_ARGS
 
 struct BA_ONCACHEVERIFYCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_CACHEVERIFYCOMPLETE_ACTION action;
 };
 
 struct BA_ONCACHEVERIFYPROGRESS_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageOrContainerId;
     LPCWSTR wzPayloadId;
     DWORD64 dw64Progress;
@@ -684,25 +689,25 @@ struct BA_ONCACHEVERIFYPROGRESS_ARGS
 
 struct BA_ONCACHEVERIFYPROGRESS_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCOMMITMSITRANSACTIONBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzTransactionId;
 };
 
 struct BA_ONCOMMITMSITRANSACTIONBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONCOMMITMSITRANSACTIONCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzTransactionId;
     HRESULT hrStatus;
     BOOTSTRAPPER_APPLY_RESTART restart;
@@ -711,13 +716,50 @@ struct BA_ONCOMMITMSITRANSACTIONCOMPLETE_ARGS
 
 struct BA_ONCOMMITMSITRANSACTIONCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION action;
 };
 
+struct BA_ONCREATE_ARGS
+{
+    DWORD dwApiVersion;
+    BOOTSTRAPPER_COMMAND command;
+    // BOOTSTRAPPER_ACTION action;
+    // BOOTSTRAPPER_DISPLAY display;
+
+    // LPWSTR wzCommandLine;
+    // INT32 nCmdShow;
+
+    // BOOTSTRAPPER_RESUME_TYPE resumeType;
+    // HWND hwndSplashScreen;
+
+    // BOOTSTRAPPER_RELATION_TYPE relationType;
+    // BOOL fPassthrough;
+
+    // LPWSTR wzLayoutDirectory;
+    // LPWSTR wzBootstrapperWorkingFolder;
+    // LPWSTR wzBootstrapperApplicationDataPath;
+};
+
+struct BA_ONCREATE_RESULTS
+{
+    DWORD dwApiVersion;
+};
+
+struct BA_ONDESTROY_ARGS
+{
+    DWORD dwApiVersion;
+    BOOL fReload;
+};
+
+struct BA_ONDESTROY_RESULTS
+{
+    DWORD dwApiVersion;
+};
+
 struct BA_ONDETECTBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_REGISTRATION_TYPE registrationType;
     DWORD cPackages;
     BOOL fCached;
@@ -725,13 +767,13 @@ struct BA_ONDETECTBEGIN_ARGS
 
 struct BA_ONDETECTBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONDETECTCOMPATIBLEMSIPACKAGE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzCompatiblePackageId;
     LPCWSTR wzCompatiblePackageVersion;
@@ -739,25 +781,25 @@ struct BA_ONDETECTCOMPATIBLEMSIPACKAGE_ARGS
 
 struct BA_ONDETECTCOMPATIBLEMSIPACKAGE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONDETECTCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
     BOOL fEligibleForCleanup;
 };
 
 struct BA_ONDETECTCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzBundleId;
     BOOTSTRAPPER_RELATION_TYPE relationType;
     LPCWSTR wzBundleTag;
@@ -768,13 +810,13 @@ struct BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_ARGS
 
 struct BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONDETECTMSIFEATURE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzFeatureId;
     BOOTSTRAPPER_FEATURE_STATE state;
@@ -782,25 +824,25 @@ struct BA_ONDETECTMSIFEATURE_ARGS
 
 struct BA_ONDETECTMSIFEATURE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONDETECTPACKAGEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
 };
 
 struct BA_ONDETECTPACKAGEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONDETECTPACKAGECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     HRESULT hrStatus;
     BOOTSTRAPPER_PACKAGE_STATE state;
@@ -809,12 +851,12 @@ struct BA_ONDETECTPACKAGECOMPLETE_ARGS
 
 struct BA_ONDETECTPACKAGECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONDETECTRELATEDBUNDLE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzBundleId;
     BOOTSTRAPPER_RELATION_TYPE relationType;
     LPCWSTR wzBundleTag;
@@ -825,13 +867,13 @@ struct BA_ONDETECTRELATEDBUNDLE_ARGS
 
 struct BA_ONDETECTRELATEDBUNDLE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONDETECTRELATEDBUNDLEPACKAGE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzBundleId;
     BOOTSTRAPPER_RELATION_TYPE relationType;
@@ -841,13 +883,13 @@ struct BA_ONDETECTRELATEDBUNDLEPACKAGE_ARGS
 
 struct BA_ONDETECTRELATEDBUNDLEPACKAGE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONDETECTRELATEDMSIPACKAGE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzUpgradeCode;
     LPCWSTR wzProductCode;
@@ -858,13 +900,13 @@ struct BA_ONDETECTRELATEDMSIPACKAGE_ARGS
 
 struct BA_ONDETECTRELATEDMSIPACKAGE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONDETECTPATCHTARGET_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzProductCode;
     BOOTSTRAPPER_PACKAGE_STATE patchState;
@@ -872,13 +914,13 @@ struct BA_ONDETECTPATCHTARGET_ARGS
 
 struct BA_ONDETECTPATCHTARGET_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONDETECTUPDATE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzUpdateLocation;
     DWORD64 dw64Size;
     LPCWSTR wzHash;
@@ -892,61 +934,61 @@ struct BA_ONDETECTUPDATE_ARGS
 
 struct BA_ONDETECTUPDATE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOL fStopProcessingUpdates;
 };
 
 struct BA_ONDETECTUPDATEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzUpdateLocation;
 };
 
 struct BA_ONDETECTUPDATEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOL fSkip;
 };
 
 struct BA_ONDETECTUPDATECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONDETECTUPDATECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fIgnoreError;
 };
 
 struct BA_ONELEVATEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONELEVATEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONELEVATECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONELEVATECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONERROR_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_ERROR_TYPE errorType;
     LPCWSTR wzPackageId;
     DWORD dwCode;
@@ -954,75 +996,75 @@ struct BA_ONERROR_ARGS
     DWORD dwUIHint;
     DWORD cData;
     LPCWSTR* rgwzData;
-    int nRecommendation;
+    INT32 nRecommendation;
 };
 
 struct BA_ONERROR_RESULTS
 {
-    DWORD cbSize;
-    int nResult;
+    DWORD dwApiVersion;
+    INT32 nResult;
 };
 
 struct BA_ONEXECUTEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD cExecutingPackages;
 };
 
 struct BA_ONEXECUTEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONEXECUTECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONEXECUTECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONEXECUTEFILESINUSE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     DWORD cFiles;
     LPCWSTR* rgwzFiles;
-    int nRecommendation;
+    INT32 nRecommendation;
     BOOTSTRAPPER_FILES_IN_USE_TYPE source;
 };
 
 struct BA_ONEXECUTEFILESINUSE_RESULTS
 {
-    DWORD cbSize;
-    int nResult;
+    DWORD dwApiVersion;
+    INT32 nResult;
 };
 
 struct BA_ONEXECUTEMSIMESSAGE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     INSTALLMESSAGE messageType;
     DWORD dwUIHint;
     LPCWSTR wzMessage;
     DWORD cData;
     LPCWSTR* rgwzData;
-    int nRecommendation;
+    INT32 nRecommendation;
 };
 
 struct BA_ONEXECUTEMSIMESSAGE_RESULTS
 {
-    DWORD cbSize;
-    int nResult;
+    DWORD dwApiVersion;
+    INT32 nResult;
 };
 
 struct BA_ONEXECUTEPACKAGEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     BOOL fExecute; // false means rollback.
     BOOTSTRAPPER_ACTION_STATE action;
@@ -1032,13 +1074,13 @@ struct BA_ONEXECUTEPACKAGEBEGIN_ARGS
 
 struct BA_ONEXECUTEPACKAGEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONEXECUTEPACKAGECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     HRESULT hrStatus;
     // Indicates whether this package requires a reboot or initiated the reboot already.
@@ -1048,26 +1090,26 @@ struct BA_ONEXECUTEPACKAGECOMPLETE_ARGS
 
 struct BA_ONEXECUTEPACKAGECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_EXECUTEPACKAGECOMPLETE_ACTION action;
 };
 
 struct BA_ONEXECUTEPATCHTARGET_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzTargetProductCode;
 };
 
 struct BA_ONEXECUTEPATCHTARGET_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONEXECUTEPROCESSCANCEL_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     DWORD dwProcessId;
     BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION recommendation;
@@ -1075,13 +1117,13 @@ struct BA_ONEXECUTEPROCESSCANCEL_ARGS
 
 struct BA_ONEXECUTEPROCESSCANCEL_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION action;
 };
 
 struct BA_ONEXECUTEPROGRESS_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     DWORD dwProgressPercentage;
     DWORD dwOverallPercentage;
@@ -1089,24 +1131,24 @@ struct BA_ONEXECUTEPROGRESS_ARGS
 
 struct BA_ONEXECUTEPROGRESS_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONLAUNCHAPPROVEDEXEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONLAUNCHAPPROVEDEXEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONLAUNCHAPPROVEDEXECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
     // Only valid if the operation succeeded.
     DWORD dwProcessId;
@@ -1114,45 +1156,45 @@ struct BA_ONLAUNCHAPPROVEDEXECOMPLETE_ARGS
 
 struct BA_ONLAUNCHAPPROVEDEXECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONPAUSEAUTOMATICUPDATESBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONPAUSEAUTOMATICUPDATESBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONPLANBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD cPackages;
 };
 
 struct BA_ONPLANBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzCompatiblePackageId;
     LPCWSTR wzCompatiblePackageVersion;
@@ -1161,14 +1203,14 @@ struct BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_ARGS
 
 struct BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOL fRequestRemove;
 };
 
 struct BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzCompatiblePackageId;
     HRESULT hrStatus;
@@ -1177,23 +1219,23 @@ struct BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_ARGS
 
 struct BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONPLANCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONPLANCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONPLANFORWARDCOMPATIBLEBUNDLE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzBundleId;
     BOOTSTRAPPER_RELATION_TYPE relationType;
     LPCWSTR wzBundleTag;
@@ -1204,14 +1246,14 @@ struct BA_ONPLANFORWARDCOMPATIBLEBUNDLE_ARGS
 
 struct BA_ONPLANFORWARDCOMPATIBLEBUNDLE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOL fIgnoreBundle;
 };
 
 struct BA_ONPLANMSIFEATURE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzFeatureId;
     BOOTSTRAPPER_FEATURE_STATE recommendedState;
@@ -1219,14 +1261,14 @@ struct BA_ONPLANMSIFEATURE_ARGS
 
 struct BA_ONPLANMSIFEATURE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_FEATURE_STATE requestedState;
     BOOL fCancel;
 };
 
 struct BA_ONPLANMSIPACKAGE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     BOOL fExecute; // false means rollback.
     BOOTSTRAPPER_ACTION_STATE action;
@@ -1235,7 +1277,7 @@ struct BA_ONPLANMSIPACKAGE_ARGS
 
 struct BA_ONPLANMSIPACKAGE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BURN_MSI_PROPERTY actionMsiProperty;
     INSTALLUILEVEL uiLevel;
@@ -1245,7 +1287,7 @@ struct BA_ONPLANMSIPACKAGE_RESULTS
 
 struct BA_ONPLANNEDCOMPATIBLEPACKAGE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzCompatiblePackageId;
     BOOL fRemove;
@@ -1253,12 +1295,12 @@ struct BA_ONPLANNEDCOMPATIBLEPACKAGE_ARGS
 
 struct BA_ONPLANNEDCOMPATIBLEPACKAGE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONPLANNEDPACKAGE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     BOOTSTRAPPER_ACTION_STATE execute;
     BOOTSTRAPPER_ACTION_STATE rollback;
@@ -1268,12 +1310,12 @@ struct BA_ONPLANNEDPACKAGE_ARGS
 
 struct BA_ONPLANNEDPACKAGE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONPLANPACKAGEBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     BOOTSTRAPPER_PACKAGE_STATE state;
     BOOL fCached;
@@ -1285,7 +1327,7 @@ struct BA_ONPLANPACKAGEBEGIN_ARGS
 
 struct BA_ONPLANPACKAGEBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOTSTRAPPER_REQUEST_STATE requestedState;
     BOOTSTRAPPER_CACHE_TYPE requestedCacheType;
@@ -1293,7 +1335,7 @@ struct BA_ONPLANPACKAGEBEGIN_RESULTS
 
 struct BA_ONPLANPACKAGECOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     HRESULT hrStatus;
     BOOTSTRAPPER_REQUEST_STATE requested;
@@ -1301,68 +1343,68 @@ struct BA_ONPLANPACKAGECOMPLETE_ARGS
 
 struct BA_ONPLANPACKAGECOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONPLANRELATEDBUNDLE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzBundleId;
     BOOTSTRAPPER_REQUEST_STATE recommendedState;
 };
 
 struct BA_ONPLANRELATEDBUNDLE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOTSTRAPPER_REQUEST_STATE requestedState;
 };
 
 struct BA_ONPLANRELATEDBUNDLETYPE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzBundleId;
     BOOTSTRAPPER_RELATED_BUNDLE_PLAN_TYPE recommendedType;
 };
 
 struct BA_ONPLANRELATEDBUNDLETYPE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOTSTRAPPER_RELATED_BUNDLE_PLAN_TYPE requestedType;
 };
 
 struct BA_ONPLANRESTORERELATEDBUNDLE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzBundleId;
     BOOTSTRAPPER_REQUEST_STATE recommendedState;
 };
 
 struct BA_ONPLANRESTORERELATEDBUNDLE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOTSTRAPPER_REQUEST_STATE requestedState;
 };
 
 struct BA_ONPLANROLLBACKBOUNDARY_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzRollbackBoundaryId;
     BOOL fRecommendedTransaction;
 };
 
 struct BA_ONPLANROLLBACKBOUNDARY_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fTransaction;
     BOOL fCancel;
 };
 
 struct BA_ONPLANPATCHTARGET_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzPackageId;
     LPCWSTR wzProductCode;
     BOOTSTRAPPER_REQUEST_STATE recommendedState;
@@ -1370,62 +1412,62 @@ struct BA_ONPLANPATCHTARGET_ARGS
 
 struct BA_ONPLANPATCHTARGET_RESULTS
 {
-    DWORD cbSize;
-    BOOTSTRAPPER_REQUEST_STATE requestedState;
+    DWORD dwApiVersion;
     BOOL fCancel;
+    BOOTSTRAPPER_REQUEST_STATE requestedState;
 };
 
 struct BA_ONPROGRESS_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD dwProgressPercentage;
     DWORD dwOverallPercentage;
 };
 
 struct BA_ONPROGRESS_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
 };
 
 struct BA_ONREGISTERBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_REGISTRATION_TYPE recommendedRegistrationType;
 };
 
 struct BA_ONREGISTERBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fCancel;
     BOOTSTRAPPER_REGISTRATION_TYPE registrationType;
 };
 
 struct BA_ONREGISTERCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONREGISTERCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONROLLBACKMSITRANSACTIONBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzTransactionId;
 };
 
 struct BA_ONROLLBACKMSITRANSACTIONBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONROLLBACKMSITRANSACTIONCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     LPCWSTR wzTransactionId;
     HRESULT hrStatus;
     BOOTSTRAPPER_APPLY_RESTART restart;
@@ -1434,99 +1476,76 @@ struct BA_ONROLLBACKMSITRANSACTIONCOMPLETE_ARGS
 
 struct BA_ONROLLBACKMSITRANSACTIONCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION action;
 };
 
-struct BA_ONSETUPDATEBEGIN_ARGS
-{
-    DWORD cbSize;
-};
-
-struct BA_ONSETUPDATEBEGIN_RESULTS
-{
-    DWORD cbSize;
-};
-
-struct BA_ONSETUPDATECOMPLETE_ARGS
-{
-    DWORD cbSize;
-    HRESULT hrStatus;
-    LPCWSTR wzPreviousPackageId;
-    LPCWSTR wzNewPackageId;
-};
-
-struct BA_ONSETUPDATECOMPLETE_RESULTS
-{
-    DWORD cbSize;
-};
-
 struct BA_ONSHUTDOWN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONSHUTDOWN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_SHUTDOWN_ACTION action;
 };
 
 struct BA_ONSTARTUP_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONSTARTUP_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONSYSTEMRESTOREPOINTBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONSYSTEMRESTOREPOINTBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONSYSTEMRESTOREPOINTCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONSYSTEMRESTOREPOINTCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
 struct BA_ONUNREGISTERBEGIN_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_REGISTRATION_TYPE recommendedRegistrationType;
 };
 
 struct BA_ONUNREGISTERBEGIN_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOTSTRAPPER_REGISTRATION_TYPE registrationType;
 };
 
 struct BA_ONUNREGISTERCOMPLETE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     HRESULT hrStatus;
 };
 
 struct BA_ONUNREGISTERCOMPLETE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
 };
 
-
+#ifdef TODO_DELETE
 
 extern "C" typedef HRESULT(WINAPI *PFN_BOOTSTRAPPER_APPLICATION_PROC)(
     __in BOOTSTRAPPER_APPLICATION_MESSAGE message,
@@ -1537,13 +1556,13 @@ extern "C" typedef HRESULT(WINAPI *PFN_BOOTSTRAPPER_APPLICATION_PROC)(
 
 struct BOOTSTRAPPER_DESTROY_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fReload;
 };
 
 struct BOOTSTRAPPER_DESTROY_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     BOOL fDisableUnloading; // indicates the BA dll must not be unloaded after BootstrapperApplicationDestroy.
 };
 
@@ -1556,7 +1575,7 @@ extern "C" typedef void (WINAPI *PFN_BOOTSTRAPPER_APPLICATION_DESTROY)(
 
 struct BOOTSTRAPPER_CREATE_ARGS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     DWORD64 qwEngineAPIVersion;
     PFN_BOOTSTRAPPER_ENGINE_PROC pfnBootstrapperEngineProc;
     LPVOID pvBootstrapperEngineProcContext;
@@ -1565,7 +1584,7 @@ struct BOOTSTRAPPER_CREATE_ARGS
 
 struct BOOTSTRAPPER_CREATE_RESULTS
 {
-    DWORD cbSize;
+    DWORD dwApiVersion;
     PFN_BOOTSTRAPPER_APPLICATION_PROC pfnBootstrapperApplicationProc;
     LPVOID pvBootstrapperApplicationProcContext;
 };
@@ -1574,3 +1593,5 @@ extern "C" typedef HRESULT(WINAPI *PFN_BOOTSTRAPPER_APPLICATION_CREATE)(
     __in const BOOTSTRAPPER_CREATE_ARGS* pArgs,
     __inout BOOTSTRAPPER_CREATE_RESULTS* pResults
     );
+
+#endif
diff --git a/src/api/burn/WixToolset.Mba.Core/BaseBootstrapperApplicationFactory.cs b/src/api/burn/WixToolset.Mba.Core/BaseBootstrapperApplicationFactory.cs
index 339bfd8f..25995e27 100644
--- a/src/api/burn/WixToolset.Mba.Core/BaseBootstrapperApplicationFactory.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BaseBootstrapperApplicationFactory.cs
@@ -6,58 +6,48 @@ namespace WixToolset.Mba.Core
     using System.Runtime.InteropServices;
 
     /// <summary>
-    /// Default implementation of <see cref="IBootstrapperApplicationFactory"/>.
+    /// This is no longer used.
     /// </summary>
+    [Obsolete("Bootstrapper applications now run out of proc and do not use a BootstrapperApplicationFactory. Remove your BootstrapperApplicationFactory class. See https://wixtoolset.org/docs/fiveforfour/ for more details.")]
     public abstract class BaseBootstrapperApplicationFactory : IBootstrapperApplicationFactory
     {
         /// <summary>
-        /// Default implementation of <see cref="IBootstrapperApplicationFactory.Create(IntPtr, IntPtr)"/>
+        /// This is no longer used.
         /// </summary>
-        /// <param name="pArgs">The args struct given by the engine when initially creating the BA.</param>
-        /// <param name="pResults">The results struct given by the engine when initially creating the BA</param>
+        /// <param name="pArgs">This is no longer used.</param>
+        /// <param name="pResults">This is no longer used.</param>
         public void Create(IntPtr pArgs, IntPtr pResults)
         {
-            InitializeFromCreateArgs(pArgs, out var engine, out var bootstrapperCommand);
-
-            var ba = this.Create(engine, bootstrapperCommand);
-            StoreBAInCreateResults(pResults, ba);
+            throw new NotImplementedException();
         }
 
         /// <summary>
-        /// Called by <see cref="BaseBootstrapperApplicationFactory.Create(IntPtr, IntPtr)"/> to get the <see cref="IBootstrapperApplication"/>.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="engine">The bundle engine.</param>
-        /// <param name="bootstrapperCommand">Command information passed from the engine for the BA to perform.</param>
-        /// <returns>The <see cref="IBootstrapperApplication"/> for the bundle.</returns>
+        /// <param name="engine">This is no longer used.</param>
+        /// <param name="bootstrapperCommand">This is no longer used.</param>
+        /// <returns>This is no longer used.</returns>
         protected abstract IBootstrapperApplication Create(IEngine engine, IBootstrapperCommand bootstrapperCommand);
 
         /// <summary>
-        /// Initializes the native part of <see cref="WixToolset.Mba.Core"/>.
-        /// Most users should inherit from <see cref="BaseBootstrapperApplicationFactory"/> instead of calling this method.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="pArgs">The args struct given by the engine when initially creating the BA.</param>
-        /// <param name="engine">The bundle engine interface.</param>
-        /// <param name="bootstrapperCommand">The context of the current run of the bundle.</param>
+        /// <param name="pArgs">This is no longer used.</param>
+        /// <param name="engine">This is no longer used.</param>
+        /// <param name="bootstrapperCommand">This is no longer used.</param>
         public static void InitializeFromCreateArgs(IntPtr pArgs, out IEngine engine, out IBootstrapperCommand bootstrapperCommand)
         {
-            Command pCommand = new Command
-            {
-                cbSize = Marshal.SizeOf(typeof(Command))
-            };
-            var pEngine = MbaNative.InitializeFromCreateArgs(pArgs, ref pCommand);
-            engine = new Engine(pEngine);
-            bootstrapperCommand = pCommand.GetBootstrapperCommand();
+            throw new NotImplementedException();
         }
 
         /// <summary>
-        /// Registers the BA with the engine using the default mapping between the message based interface and the COM interface.
-        /// Most users should inherit from <see cref="BaseBootstrapperApplicationFactory"/> instead of calling this method.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="pResults">The results struct given by the engine when initially creating the BA</param>
-        /// <param name="ba">The <see cref="IBootstrapperApplication"/>.</param>
+        /// <param name="pResults">This is no longer used.</param>
+        /// <param name="ba">This is no longer used.</param>
         public static void StoreBAInCreateResults(IntPtr pResults, IBootstrapperApplication ba)
         {
-            MbaNative.StoreBAInCreateResults(pResults, ba);
+            throw new NotImplementedException();
         }
     }
 }
diff --git a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
index a0ec6ab9..98b34217 100644
--- a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
@@ -13,23 +13,15 @@ namespace WixToolset.Mba.Core
     public abstract class BootstrapperApplication : MarshalByRefObject, IDefaultBootstrapperApplication
     {
         /// <summary>
-        /// Specifies whether this bootstrapper should run asynchronously. The default is true.
-        /// </summary>
-        protected readonly bool asyncExecution;
-
-        /// <summary>
         /// Gets the <see cref="IEngine"/> for interaction with the engine.
         /// </summary>
-        protected readonly IEngine engine;
+        protected IEngine engine;
 
-        /// <summary>
-        /// Creates a new instance of the <see cref="BootstrapperApplication"/> class.
-        /// </summary>
-        protected BootstrapperApplication(IEngine engine)
-        {
-            this.engine = engine;
-            this.asyncExecution = true;
-        }
+        /// <inheritdoc/>
+        public event EventHandler<CreateEventArgs> Create;
+
+        /// <inheritdoc/>
+        public event EventHandler<DestroyEventArgs> Destroy;
 
         /// <inheritdoc/>
         public event EventHandler<StartupEventArgs> Startup;
@@ -266,12 +258,6 @@ namespace WixToolset.Mba.Core
         public event EventHandler<CachePayloadExtractCompleteEventArgs> CachePayloadExtractComplete;
 
         /// <inheritdoc/>
-        public event EventHandler<SetUpdateBeginEventArgs> SetUpdateBegin;
-
-        /// <inheritdoc/>
-        public event EventHandler<SetUpdateCompleteEventArgs> SetUpdateComplete;
-
-        /// <inheritdoc/>
         public event EventHandler<PlanRestoreRelatedBundleEventArgs> PlanRestoreRelatedBundle;
 
         /// <inheritdoc/>
@@ -284,35 +270,73 @@ namespace WixToolset.Mba.Core
         public event EventHandler<CachePackageNonVitalValidationFailureEventArgs> CachePackageNonVitalValidationFailure;
 
         /// <summary>
+        /// The default constructor.
+        /// </summary>
+        /// <remarks>
+        /// The engine object will be valid after handling the OnCreate() event.
+        /// </remarks>
+        protected BootstrapperApplication()
+        {
+        }
+
+        /// <summary>
+        /// This constructor is no longer used.
+        /// </summary>
+        [Obsolete("This constructor is no longer used. Use the default constructor. The engine object will be valid after handling the OnCreate() event.")]
+        protected BootstrapperApplication(IEngine engine)
+        {
+            throw new NotImplementedException("This constructor is no longer used. Use the default constructor. The engine object will be valid after handling the OnCreate() event.");
+        }
+
+        /// <summary>
         /// Entry point that is called when the bootstrapper application is ready to run.
         /// </summary>
         protected abstract void Run();
 
         /// <summary>
-        /// Called by the engine, raises the <see cref="Startup"/> event.
+        /// Called by the engine, raises the <see cref="Create"/> event.
         /// </summary>
         /// <param name="args">Additional arguments for this event.</param>
-        protected virtual void OnStartup(StartupEventArgs args)
+        protected virtual void OnCreate(CreateEventArgs args)
         {
-            EventHandler<StartupEventArgs> handler = this.Startup;
+            this.engine = args.Engine;
+
+            EventHandler<CreateEventArgs> handler = this.Create;
             if (null != handler)
             {
                 handler(this, args);
             }
+        }
 
-            if (this.asyncExecution)
+        /// <summary>
+        /// Called by the engine, raises the <see cref="Destroy"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDestroy(DestroyEventArgs args)
+        {
+            EventHandler<DestroyEventArgs> handler = this.Destroy;
+            if (null != handler)
             {
-                this.engine.Log(LogLevel.Verbose, "Creating BA thread to run asynchronously.");
-                Thread uiThread = new Thread(this.Run);
-                uiThread.Name = "UIThread";
-                uiThread.SetApartmentState(ApartmentState.STA);
-                uiThread.Start();
+                handler(this, args);
             }
-            else
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="Startup"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnStartup(StartupEventArgs args)
+        {
+            EventHandler<StartupEventArgs> handler = this.Startup;
+            if (null != handler)
             {
-                this.engine.Log(LogLevel.Verbose, "Creating BA thread to run synchronously.");
-                this.Run();
+                handler(this, args);
             }
+
+            Thread uiThread = new Thread(this.Run);
+            uiThread.Name = "UIThread";
+            uiThread.SetApartmentState(ApartmentState.STA);
+            uiThread.Start();
         }
 
         /// <summary>
@@ -1315,31 +1339,6 @@ namespace WixToolset.Mba.Core
             }
         }
 
-        /// <summary>
-        /// Called by the engine, raises the <see cref="SetUpdateBegin"/> event.
-        /// </summary>
-        /// <param name="args">Additional arguments for this event.</param>
-        protected virtual void OnSetUpdateBegin(SetUpdateBeginEventArgs args)
-        {
-            EventHandler<SetUpdateBeginEventArgs> handler = this.SetUpdateBegin;
-            if (null != handler)
-            {
-                handler(this, args);
-            }
-        }
-
-        /// <summary>
-        /// Called by the engine, raises the <see cref="SetUpdateComplete"/> event.
-        /// </summary>
-        /// <param name="args">Additional arguments for this event.</param>
-        protected virtual void OnSetUpdateComplete(SetUpdateCompleteEventArgs args)
-        {
-            EventHandler<SetUpdateCompleteEventArgs> handler = this.SetUpdateComplete;
-            if (null != handler)
-            {
-                handler(this, args);
-            }
-        }
 
         /// <summary>
         /// Called by the engine, raises the <see cref="PlanRestoreRelatedBundle"/> event.
@@ -1395,7 +1394,7 @@ namespace WixToolset.Mba.Core
 
         #region IBootstrapperApplication Members
 
-        int IBootstrapperApplication.BAProc(int message, IntPtr pvArgs, IntPtr pvResults, IntPtr pvContext)
+        int IBootstrapperApplication.BAProc(int message, IntPtr pvArgs, IntPtr pvResults)
         {
             switch (message)
             {
@@ -1404,8 +1403,24 @@ namespace WixToolset.Mba.Core
             }
         }
 
-        void IBootstrapperApplication.BAProcFallback(int message, IntPtr pvArgs, IntPtr pvResults, ref int phr, IntPtr pvContext)
+        void IBootstrapperApplication.BAProcFallback(int message, IntPtr pvArgs, IntPtr pvResults, ref int phr)
+        {
+        }
+
+        int IBootstrapperApplication.OnCreate(IBootstrapperEngine engine, ref Command command)
         {
+            CreateEventArgs args = new CreateEventArgs(new Engine(engine), command.GetBootstrapperCommand());
+            this.OnCreate(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDestroy(bool reload)
+        {
+            DestroyEventArgs args = new DestroyEventArgs(reload);
+            this.OnDestroy(args);
+
+            return args.HResult;
         }
 
         int IBootstrapperApplication.OnStartup()
@@ -2107,22 +2122,6 @@ namespace WixToolset.Mba.Core
             return args.HResult;
         }
 
-        int IBootstrapperApplication.OnSetUpdateBegin()
-        {
-            SetUpdateBeginEventArgs args = new SetUpdateBeginEventArgs();
-            this.OnSetUpdateBegin(args);
-
-            return args.HResult;
-        }
-
-        int IBootstrapperApplication.OnSetUpdateComplete(int hrStatus, string wzPreviousPackageId, string wzNewPackageId)
-        {
-            SetUpdateCompleteEventArgs args = new SetUpdateCompleteEventArgs(hrStatus, wzPreviousPackageId, wzNewPackageId);
-            this.OnSetUpdateComplete(args);
-
-            return args.HResult;
-        }
-
         int IBootstrapperApplication.OnPlanRestoreRelatedBundle(string wzBundleId, RequestState recommendedState, ref RequestState pRequestedState, ref bool fCancel)
         {
             PlanRestoreRelatedBundleEventArgs args = new PlanRestoreRelatedBundleEventArgs(wzBundleId, recommendedState, pRequestedState, fCancel);
diff --git a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplicationFactoryAttribute.cs b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplicationFactoryAttribute.cs
index 95252cf3..6b465408 100644
--- a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplicationFactoryAttribute.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplicationFactoryAttribute.cs
@@ -5,31 +5,27 @@ namespace WixToolset.Mba.Core
     using System;
 
     /// <summary>
-    /// Identifies the bootstrapper application factory class.
+    /// This is no longer used.
     /// </summary>
-    /// <remarks>
-    /// This required assembly attribute identifies the bootstrapper application factory class.
-    /// </remarks>
+    [Obsolete("Bootstrapper applications now run out of proc and do not use a BootstrapperApplicationFactory. Remove your BootstrapperApplicationFactory class. See https://wixtoolset.org/docs/fiveforfour/ for more details.")]
     [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = false)]
     public sealed class BootstrapperApplicationFactoryAttribute : Attribute
     {
-        private Type bootstrapperApplicationFactoryType;
-
         /// <summary>
-        /// Creates a new instance of the <see cref="BootstrapperApplicationFactoryAttribute"/> class.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="bootstrapperApplicationFactoryType">The <see cref="Type"/> of the BA factory.</param>
+        /// <param name="bootstrapperApplicationFactoryType">This is no longer used</param>
         public BootstrapperApplicationFactoryAttribute(Type bootstrapperApplicationFactoryType)
         {
-            this.bootstrapperApplicationFactoryType = bootstrapperApplicationFactoryType;
+            throw new NotImplementedException();
         }
 
         /// <summary>
-        /// Gets the type of the bootstrapper application factory class to create.
+        /// This is no longer used.
         /// </summary>
         public Type BootstrapperApplicationFactoryType
         {
-            get { return this.bootstrapperApplicationFactoryType; }
+            get { throw new NotImplementedException(); }
         }
     }
 }
diff --git a/src/api/burn/WixToolset.Mba.Core/BootstrapperCommand.cs b/src/api/burn/WixToolset.Mba.Core/BootstrapperCommand.cs
index ed1dc191..b96a8f95 100644
--- a/src/api/burn/WixToolset.Mba.Core/BootstrapperCommand.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BootstrapperCommand.cs
@@ -3,11 +3,55 @@
 namespace WixToolset.Mba.Core
 {
     using System;
+    using System.CodeDom.Compiler;
     using System.Collections.Generic;
     using System.ComponentModel;
     using System.Runtime.InteropServices;
 
     /// <summary>
+    /// Command-line provided to the bootstrapper application.
+    /// </summary>
+    [Serializable]
+    [StructLayout(LayoutKind.Sequential)]
+    [GeneratedCodeAttribute("WixToolset.Bootstrapper.InteropCodeGenerator", "1.0.0.0")]
+    public struct Command
+    {
+        // Strings must be declared as pointers so that Marshaling doesn't free them.
+        [MarshalAs(UnmanagedType.I4)] internal int cbSize;
+        [MarshalAs(UnmanagedType.U4)] private readonly LaunchAction action;
+        [MarshalAs(UnmanagedType.U4)] private readonly Display display;
+        private readonly IntPtr wzCommandLine;
+        [MarshalAs(UnmanagedType.I4)] private readonly int nCmdShow;
+        [MarshalAs(UnmanagedType.U4)] private readonly ResumeType resume;
+        private readonly IntPtr hwndSplashScreen;
+        [MarshalAs(UnmanagedType.I4)] private readonly RelationType relation;
+        [MarshalAs(UnmanagedType.Bool)] private readonly bool passthrough;
+        private readonly IntPtr wzLayoutDirectory;
+        private readonly IntPtr wzBootstrapperWorkingFolder;
+        private readonly IntPtr wzBootstrapperApplicationDataPath;
+
+        /// <summary>
+        /// Gets the IBootstrapperCommand for this Command.
+        /// </summary>
+        /// <returns>IBootstrapperCommand</returns>
+        public IBootstrapperCommand GetBootstrapperCommand()
+        {
+            return new BootstrapperCommand(
+                this.action,
+                this.display,
+                Marshal.PtrToStringUni(this.wzCommandLine),
+                this.nCmdShow,
+                this.resume,
+                this.hwndSplashScreen,
+                this.relation,
+                this.passthrough,
+                Marshal.PtrToStringUni(this.wzLayoutDirectory),
+                Marshal.PtrToStringUni(this.wzBootstrapperWorkingFolder),
+                Marshal.PtrToStringUni(this.wzBootstrapperApplicationDataPath));
+        }
+    }
+
+    /// <summary>
     /// Default implementation of <see cref="IBootstrapperCommand"/>.
     /// </summary>
     public sealed class BootstrapperCommand : IBootstrapperCommand
diff --git a/src/api/burn/WixToolset.Mba.Core/BundleInfo.cs b/src/api/burn/WixToolset.Mba.Core/BundleInfo.cs
index ee751ebf..0039f375 100644
--- a/src/api/burn/WixToolset.Mba.Core/BundleInfo.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BundleInfo.cs
@@ -34,17 +34,17 @@ namespace WixToolset.Mba.Core
         }
 
         /// <inheritdoc/>
-        public IPackageInfo AddRelatedBundleAsPackage(DetectRelatedBundleEventArgs e)
+        public IPackageInfo AddRelatedBundleAsPackage(string productCode, RelationType relationType, bool perMachine, string version)
         {
-            var package = PackageInfo.GetRelatedBundleAsPackage(e.ProductCode, e.RelationType, e.PerMachine, e.Version);
+            var package = PackageInfo.GetRelatedBundleAsPackage(productCode, relationType, perMachine, version);
             this.Packages.Add(package.Id, package);
             return package;
         }
 
         /// <inheritdoc/>
-        public IPackageInfo AddUpdateBundleAsPackage(SetUpdateCompleteEventArgs e)
+        public IPackageInfo AddUpdateBundleAsPackage(string packageId)
         {
-            var package = PackageInfo.GetUpdateBundleAsPackage(e.NewPackageId);
+            var package = PackageInfo.GetUpdateBundleAsPackage(packageId);
             this.Packages.Add(package.Id, package);
             return package;
         }
diff --git a/src/api/burn/WixToolset.Mba.Core/Engine.cs b/src/api/burn/WixToolset.Mba.Core/Engine.cs
index 1120fb1c..df412e8c 100644
--- a/src/api/burn/WixToolset.Mba.Core/Engine.cs
+++ b/src/api/burn/WixToolset.Mba.Core/Engine.cs
@@ -253,9 +253,9 @@ namespace WixToolset.Mba.Core
         }
 
         /// <inheritdoc/>
-        public void SetUpdate(string localSource, string downloadSource, long size, UpdateHashType hashType, string hash)
+        public void SetUpdate(string localSource, string downloadSource, long size, UpdateHashType hashType, string hash, string updatePackageId)
         {
-            this.engine.SetUpdate(localSource, downloadSource, size, hashType, hash);
+            this.engine.SetUpdate(localSource, downloadSource, size, hashType, hash, updatePackageId);
         }
 
         /// <inheritdoc/>
diff --git a/src/api/burn/WixToolset.Mba.Core/EventArgs.cs b/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
index 4b7f2245..6506c840 100644
--- a/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
+++ b/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
@@ -198,6 +198,54 @@ namespace WixToolset.Mba.Core
     }
 
     /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.Create"/>.
+    /// </summary>
+    [Serializable]
+    public class CreateEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CreateEventArgs(IEngine engine, IBootstrapperCommand command)
+        {
+            this.Engine = engine;
+            this.Command = command;
+        }
+
+        /// <summary>
+        /// Engine running the application.
+        /// </summary>
+        public IEngine Engine { get; }
+
+        /// <summary>
+        /// Command line arguments.
+        /// </summary>
+        public IBootstrapperCommand Command { get; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.Destroy"/>.
+    /// </summary>
+    [Serializable]
+    public class DestroyEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DestroyEventArgs(bool reload)
+        {
+            this.Reload = reload;
+        }
+
+        /// <summary>
+        /// Bootstrapper application is being reloaded.
+        /// </summary>
+        public bool Reload { get; }
+    }
+
+    /// <summary>
     /// Event arguments for <see cref="IDefaultBootstrapperApplication.Startup"/>.
     /// </summary>
     [Serializable]
@@ -2567,49 +2615,6 @@ namespace WixToolset.Mba.Core
     }
 
     /// <summary>
-    /// EventArgs for <see cref="IDefaultBootstrapperApplication.SetUpdateBegin"/>.
-    /// </summary>
-    [Serializable]
-    public class SetUpdateBeginEventArgs : HResultEventArgs
-    {
-        /// <summary>
-        /// This class is for events raised by the engine.
-        /// It is not intended to be instantiated by user code.
-        /// </summary>
-        public SetUpdateBeginEventArgs()
-        {
-        }
-    }
-
-    /// <summary>
-    /// Event arguments for <see cref="IDefaultBootstrapperApplication.SetUpdateComplete"/>
-    /// </summary>
-    [Serializable]
-    public class SetUpdateCompleteEventArgs : StatusEventArgs
-    {
-        /// <summary>
-        /// This class is for events raised by the engine.
-        /// It is not intended to be instantiated by user code.
-        /// </summary>
-        public SetUpdateCompleteEventArgs(int hrStatus, string previousPackageId, string newPackageId)
-            : base(hrStatus)
-        {
-            this.PreviousPackageId = previousPackageId;
-            this.NewPackageId = newPackageId;
-        }
-
-        /// <summary>
-        /// Gets the identifier of the update package that was removed.
-        /// </summary>
-        public string PreviousPackageId { get; private set; }
-
-        /// <summary>
-        /// Gets the identifier of the update package that was added.
-        /// </summary>
-        public string NewPackageId { get; private set; }
-    }
-
-    /// <summary>
     /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanRestoreRelatedBundle"/>
     /// </summary>
     [Serializable]
diff --git a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
index 36c7fd33..8a255c44 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
@@ -21,8 +21,7 @@ namespace WixToolset.Mba.Core
         int BAProc(
             int message,
             IntPtr pvArgs,
-            IntPtr pvResults,
-            IntPtr pvContext
+            IntPtr pvResults
             );
 
         /// <summary>
@@ -32,11 +31,24 @@ namespace WixToolset.Mba.Core
             int message,
             IntPtr pvArgs,
             IntPtr pvResults,
-            ref int phr,
-            IntPtr pvContext
+            ref int phr
             );
 
         /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.Create"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCreate(IBootstrapperEngine engine, ref Command command);
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.Destroy"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDestroy(bool reload);
+
+        /// <summary>
         /// See <see cref="IDefaultBootstrapperApplication.Startup"/>.
         /// </summary>
         [PreserveSig]
@@ -940,24 +952,6 @@ namespace WixToolset.Mba.Core
             );
 
         /// <summary>
-        /// See <see cref="IDefaultBootstrapperApplication.SetUpdateBegin"/>.
-        /// </summary>
-        [PreserveSig]
-        [return: MarshalAs(UnmanagedType.I4)]
-        int OnSetUpdateBegin();
-
-        /// <summary>
-        /// See <see cref="IDefaultBootstrapperApplication.SetUpdateComplete"/>.
-        /// </summary>
-        [PreserveSig]
-        [return: MarshalAs(UnmanagedType.I4)]
-        int OnSetUpdateComplete(
-            int hrStatus,
-            [MarshalAs(UnmanagedType.LPWStr)] string wzPreviousPackageId,
-            [MarshalAs(UnmanagedType.LPWStr)] string wzNewPackageId
-            );
-
-        /// <summary>
         /// See <see cref="IDefaultBootstrapperApplication.PlanRestoreRelatedBundle"/>.
         /// </summary>
         [PreserveSig]
diff --git a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplicationFactory.cs b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplicationFactory.cs
index 2e84de67..393c7e31 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplicationFactory.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplicationFactory.cs
@@ -7,58 +7,16 @@ namespace WixToolset.Mba.Core
     using System.Runtime.InteropServices;
 
     /// <summary>
-    /// Interface used by the native host to dynamically load the BA.
+    /// This is no longer used.
     /// </summary>
-    [ComVisible(true)]
-    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
-    [Guid("2965A12F-AC7B-43A0-85DF-E4B2168478A4")]
-    [GeneratedCodeAttribute("WixToolset.Bootstrapper.InteropCodeGenerator", "1.0.0.0")]
+    [Obsolete("Bootstrapper applications now run out of proc and do not use a BootstrapperApplicationFactory. Remove your BootstrapperApplicationFactory class. See https://wixtoolset.org/docs/fiveforfour/ for more details.")]
     public interface IBootstrapperApplicationFactory
     {
         /// <summary>
-        /// Low level method called by the native host.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="pArgs"></param>
-        /// <param name="pResults"></param>
-        void Create(
-            IntPtr pArgs,
-            IntPtr pResults
-            );
-    }
-
-    [Serializable]
-    [StructLayout(LayoutKind.Sequential)]
-    [GeneratedCodeAttribute("WixToolset.Bootstrapper.InteropCodeGenerator", "1.0.0.0")]
-    internal struct Command
-    {
-        // Strings must be declared as pointers so that Marshaling doesn't free them.
-        [MarshalAs(UnmanagedType.I4)] internal int cbSize;
-        [MarshalAs(UnmanagedType.U4)] private readonly LaunchAction action;
-        [MarshalAs(UnmanagedType.U4)] private readonly Display display;
-        private readonly IntPtr wzCommandLine;
-        [MarshalAs(UnmanagedType.I4)] private readonly int nCmdShow;
-        [MarshalAs(UnmanagedType.U4)] private readonly ResumeType resume;
-        private readonly IntPtr hwndSplashScreen;
-        [MarshalAs(UnmanagedType.I4)] private readonly RelationType relation;
-        [MarshalAs(UnmanagedType.Bool)] private readonly bool passthrough;
-        private readonly IntPtr wzLayoutDirectory;
-        private readonly IntPtr wzBootstrapperWorkingFolder;
-        private readonly IntPtr wzBootstrapperApplicationDataPath;
-
-        public IBootstrapperCommand GetBootstrapperCommand()
-        {
-            return new BootstrapperCommand(
-                this.action,
-                this.display,
-                Marshal.PtrToStringUni(this.wzCommandLine),
-                this.nCmdShow,
-                this.resume,
-                this.hwndSplashScreen,
-                this.relation,
-                this.passthrough,
-                Marshal.PtrToStringUni(this.wzLayoutDirectory),
-                Marshal.PtrToStringUni(this.wzBootstrapperWorkingFolder),
-                Marshal.PtrToStringUni(this.wzBootstrapperApplicationDataPath));
-        }
+        /// <param name="pArgs">This is no longer used.</param>
+        /// <param name="pResults">This is no longer used.</param>
+        void Create(IntPtr pArgs, IntPtr pResults);
     }
 }
diff --git a/src/api/burn/WixToolset.Mba.Core/IBootstrapperEngine.cs b/src/api/burn/WixToolset.Mba.Core/IBootstrapperEngine.cs
index 3f90639f..a175bead 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBootstrapperEngine.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBootstrapperEngine.cs
@@ -108,14 +108,15 @@ namespace WixToolset.Mba.Core
             );
 
         /// <summary>
-        /// See <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string)"/>.
+        /// See <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string, string)"/>.
         /// </summary>
         void SetUpdate(
             [MarshalAs(UnmanagedType.LPWStr)] string wzLocalSource,
             [MarshalAs(UnmanagedType.LPWStr)] string wzDownloadSource,
             [MarshalAs(UnmanagedType.U8)] long qwValue,
             [MarshalAs(UnmanagedType.U4)] UpdateHashType hashType,
-            [MarshalAs(UnmanagedType.LPWStr)] string wzHash
+            [MarshalAs(UnmanagedType.LPWStr)] string wzHash,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzUpdatePackageId
             );
 
         /// <summary>
@@ -330,12 +331,12 @@ namespace WixToolset.Mba.Core
         Repair,
 
         /// <summary>
-        /// Launch the update registered with <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string)"/> and then exit without waiting for it to complete.
+        /// Launch the update registered with <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string, string)"/> and then exit without waiting for it to complete.
         /// </summary>
         UpdateReplace,
 
         /// <summary>
-        /// Launch the update registered with <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string)"/> as an embedded bundle.
+        /// Launch the update registered with <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string, string)"/> as an embedded bundle.
         /// </summary>
         UpdateReplaceEmbedded,
     }
diff --git a/src/api/burn/WixToolset.Mba.Core/IBundleInfo.cs b/src/api/burn/WixToolset.Mba.Core/IBundleInfo.cs
index 951f511a..3c52fc02 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBundleInfo.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBundleInfo.cs
@@ -37,15 +37,18 @@ namespace WixToolset.Mba.Core
         /// <summary>
         /// Adds a related bundle as a package.
         /// </summary>
-        /// <param name="e"></param>
+        /// <param name="productCode"></param>
+        /// <param name="relationType"></param>
+        /// <param name="perMachine"></param>
+        /// <param name="version"></param>
         /// <returns>The created <see cref="IPackageInfo"/>.</returns>
-        IPackageInfo AddRelatedBundleAsPackage(DetectRelatedBundleEventArgs e);
+        IPackageInfo AddRelatedBundleAsPackage(string productCode, RelationType relationType, bool perMachine, string version);
 
         /// <summary>
         /// Adds an update bundle as a package.
         /// </summary>
-        /// <param name="e"></param>
+        /// <param name="packageId">Package id added as update bundle.</param>
         /// <returns>The created <see cref="IPackageInfo"/>.</returns>
-        IPackageInfo AddUpdateBundleAsPackage(SetUpdateCompleteEventArgs e);
+        IPackageInfo AddUpdateBundleAsPackage(string packageId);
     }
 }
diff --git a/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs
index 2fa88bdb..51ea4e4d 100644
--- a/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs
@@ -139,6 +139,16 @@ namespace WixToolset.Mba.Core
         event EventHandler<CommitMsiTransactionCompleteEventArgs> CommitMsiTransactionComplete;
 
         /// <summary>
+        /// Fired when the application is being created.
+        /// </summary>
+        event EventHandler<CreateEventArgs> Create;
+
+        /// <summary>
+        /// Fired when the application is being destroyed.
+        /// </summary>
+        event EventHandler<DestroyEventArgs> Destroy;
+
+        /// <summary>
         /// Fired when the overall detection phase has begun.
         /// </summary>
         event EventHandler<DetectBeginEventArgs> DetectBegin;
@@ -394,16 +404,6 @@ namespace WixToolset.Mba.Core
         event EventHandler<RollbackMsiTransactionCompleteEventArgs> RollbackMsiTransactionComplete;
 
         /// <summary>
-        /// Fired when the engine has begun to setup the update package.
-        /// </summary>
-        event EventHandler<SetUpdateBeginEventArgs> SetUpdateBegin;
-
-        /// <summary>
-        /// Fired when the engine has completed setting up the update package.
-        /// </summary>
-        event EventHandler<SetUpdateCompleteEventArgs> SetUpdateComplete;
-
-        /// <summary>
         /// Fired when the engine is shutting down the bootstrapper application.
         /// </summary>
         event EventHandler<ShutdownEventArgs> Shutdown;
diff --git a/src/api/burn/WixToolset.Mba.Core/IEngine.cs b/src/api/burn/WixToolset.Mba.Core/IEngine.cs
index 7ffa80d7..dde97a70 100644
--- a/src/api/burn/WixToolset.Mba.Core/IEngine.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IEngine.cs
@@ -149,7 +149,8 @@ namespace WixToolset.Mba.Core
         /// <param name="size">Size of the expected update.</param>
         /// <param name="hashType">Type of the hash expected on the update.</param>
         /// <param name="hash">Optional hash expected for the update.</param>
-        void SetUpdate(string localSource, string downloadSource, long size, UpdateHashType hashType, string hash);
+        /// <param name="updatePackageId">Optional package id for the update.</param>
+        void SetUpdate(string localSource, string downloadSource, long size, UpdateHashType hashType, string hash, string updatePackageId);
 
         /// <summary>
         /// Sets the URL to the update feed.
diff --git a/src/api/burn/WixToolset.Mba.Core/ManagedBootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/ManagedBootstrapperApplication.cs
new file mode 100644
index 00000000..74bfbd73
--- /dev/null
+++ b/src/api/burn/WixToolset.Mba.Core/ManagedBootstrapperApplication.cs
@@ -0,0 +1,19 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+namespace WixToolset.Mba.Core
+{
+    /// <summary>
+    /// Managed bootstrapper application entry point.
+    /// </summary>
+    public static class ManagedBootstrapperApplication
+    {
+        /// <summary>
+        /// Run the managed bootstrapper application.
+        /// </summary>
+        /// <param name="application">Bootstrapper applciation to run.</param>
+        public static void Run(IBootstrapperApplication application)
+        {
+            MbaNative.BootstrapperApplicationRun(application);
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.Mba.Core/MbaNative.cs b/src/api/burn/WixToolset.Mba.Core/MbaNative.cs
index a68a3907..e8e9d576 100644
--- a/src/api/burn/WixToolset.Mba.Core/MbaNative.cs
+++ b/src/api/burn/WixToolset.Mba.Core/MbaNative.cs
@@ -8,14 +8,10 @@ namespace WixToolset.Mba.Core
     internal static class MbaNative
     {
         [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
-        internal static extern IBootstrapperEngine InitializeFromCreateArgs(
-            IntPtr pArgs,
-            ref Command pCommand
-            );
+        internal static extern void BootstrapperApplicationDebuggerCheck();
 
-        [DllImport("mbanative.dll", ExactSpelling = true)]
-        internal static extern void StoreBAInCreateResults(
-            IntPtr pResults,
+        [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
+        internal static extern void BootstrapperApplicationRun(
             [MarshalAs(UnmanagedType.Interface)] IBootstrapperApplication pBA
             );
     }
diff --git a/src/api/burn/WixToolset.Mba.Core/PackageInfo.cs b/src/api/burn/WixToolset.Mba.Core/PackageInfo.cs
index c6373647..b91c52c9 100644
--- a/src/api/burn/WixToolset.Mba.Core/PackageInfo.cs
+++ b/src/api/burn/WixToolset.Mba.Core/PackageInfo.cs
@@ -365,19 +365,19 @@ namespace WixToolset.Mba.Core
                 package.DisplayInternalUICondition = BootstrapperApplicationData.GetAttribute(node, "DisplayInternalUICondition");
             }
 
-            nodes = root.Select("/p:BootstrapperApplicationData/p:WixMbaPrereqInformation", namespaceManager);
+            nodes = root.Select("/p:BootstrapperApplicationData/p:WixPrereqInformation", namespaceManager);
 
             foreach (XPathNavigator node in nodes)
             {
                 string id = BootstrapperApplicationData.GetAttribute(node, "PackageId");
                 if (id == null)
                 {
-                    throw new Exception("Failed to get package identifier for WixMbaPrereqInformation.");
+                    throw new Exception("Failed to get package identifier for WixPrereqInformation.");
                 }
 
                 if (!packagesById.TryGetValue(id, out var ipackage))
                 {
-                    throw new Exception(String.Format("Failed to find package specified in WixMbaPrereqInformation: {0}", id));
+                    throw new Exception(String.Format("Failed to find package specified in WixPrereqInformation: {0}", id));
                 }
 
                 var package = (PackageInfo)ipackage;
diff --git a/src/api/burn/balutil/BalBaseBAFunctionsProc.cpp b/src/api/burn/balutil/BalBaseBAFunctionsProc.cpp
new file mode 100644
index 00000000..38ebf65c
--- /dev/null
+++ b/src/api/burn/balutil/BalBaseBAFunctionsProc.cpp
@@ -0,0 +1,1099 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+#include "precomp.h"
+
+static HRESULT BalBaseBAFunctionsProcOnDestroy(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDESTROY_ARGS* pArgs,
+    __inout BA_ONDESTROY_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnDestroy(pArgs->fReload);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTBEGIN_ARGS* pArgs,
+    __inout BA_ONDETECTBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectBegin(pArgs->fCached, pArgs->registrationType, pArgs->cPackages, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTCOMPLETE_ARGS* pArgs,
+    __inout BA_ONDETECTCOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnDetectComplete(pArgs->hrStatus, pArgs->fEligibleForCleanup);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANBEGIN_ARGS* pArgs,
+    __inout BA_ONPLANBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanBegin(pArgs->cPackages, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANCOMPLETE_ARGS* pArgs,
+    __inout BA_ONPLANCOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnPlanComplete(pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnStartup(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONSTARTUP_ARGS* /*pArgs*/,
+    __inout BA_ONSTARTUP_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnStartup();
+}
+
+static HRESULT BalBaseBAFunctionsProcOnShutdown(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONSHUTDOWN_ARGS* /*pArgs*/,
+    __inout BA_ONSHUTDOWN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnShutdown(&pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectForwardCompatibleBundle(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_ARGS* pArgs,
+    __inout BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectForwardCompatibleBundle(pArgs->wzBundleId, pArgs->relationType, pArgs->wzBundleTag, pArgs->fPerMachine, pArgs->wzVersion, pArgs->fMissingFromCache, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectUpdateBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTUPDATEBEGIN_ARGS* pArgs,
+    __inout BA_ONDETECTUPDATEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectUpdateBegin(pArgs->wzUpdateLocation, &pResults->fCancel, &pResults->fSkip);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectUpdate(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTUPDATE_ARGS* pArgs,
+    __inout BA_ONDETECTUPDATE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectUpdate(pArgs->wzUpdateLocation, pArgs->dw64Size, pArgs->wzHash, pArgs->hashAlgorithm, pArgs->wzVersion, pArgs->wzTitle, pArgs->wzSummary, pArgs->wzContentType, pArgs->wzContent, &pResults->fCancel, &pResults->fStopProcessingUpdates);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectUpdateComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTUPDATECOMPLETE_ARGS* pArgs,
+    __inout BA_ONDETECTUPDATECOMPLETE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectUpdateComplete(pArgs->hrStatus, &pResults->fIgnoreError);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectRelatedBundle(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTRELATEDBUNDLE_ARGS* pArgs,
+    __inout BA_ONDETECTRELATEDBUNDLE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectRelatedBundle(pArgs->wzBundleId, pArgs->relationType, pArgs->wzBundleTag, pArgs->fPerMachine, pArgs->wzVersion, pArgs->fMissingFromCache, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectPackageBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTPACKAGEBEGIN_ARGS* pArgs,
+    __inout BA_ONDETECTPACKAGEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectPackageBegin(pArgs->wzPackageId, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectCompatiblePackage(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTCOMPATIBLEMSIPACKAGE_ARGS* pArgs,
+    __inout BA_ONDETECTCOMPATIBLEMSIPACKAGE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectCompatibleMsiPackage(pArgs->wzPackageId, pArgs->wzCompatiblePackageId, pArgs->wzCompatiblePackageVersion, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectRelatedMsiPackage(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTRELATEDMSIPACKAGE_ARGS* pArgs,
+    __inout BA_ONDETECTRELATEDMSIPACKAGE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectRelatedMsiPackage(pArgs->wzPackageId, pArgs->wzUpgradeCode, pArgs->wzProductCode, pArgs->fPerMachine, pArgs->wzVersion, pArgs->operation, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectPatchTarget(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTPATCHTARGET_ARGS* pArgs,
+    __inout BA_ONDETECTPATCHTARGET_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectPatchTarget(pArgs->wzPackageId, pArgs->wzProductCode, pArgs->patchState, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectMsiFeature(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTMSIFEATURE_ARGS* pArgs,
+    __inout BA_ONDETECTMSIFEATURE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectMsiFeature(pArgs->wzPackageId, pArgs->wzFeatureId, pArgs->state, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectPackageComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTPACKAGECOMPLETE_ARGS* pArgs,
+    __inout BA_ONDETECTPACKAGECOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnDetectPackageComplete(pArgs->wzPackageId, pArgs->hrStatus, pArgs->state, pArgs->fCached);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanRelatedBundle(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANRELATEDBUNDLE_ARGS* pArgs,
+    __inout BA_ONPLANRELATEDBUNDLE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanRelatedBundle(pArgs->wzBundleId, pArgs->recommendedState, &pResults->requestedState, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanRollbackBoundary(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANROLLBACKBOUNDARY_ARGS* pArgs,
+    __inout BA_ONPLANROLLBACKBOUNDARY_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanRollbackBoundary(pArgs->wzRollbackBoundaryId, pArgs->fRecommendedTransaction, &pResults->fTransaction, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanPackageBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANPACKAGEBEGIN_ARGS* pArgs,
+    __inout BA_ONPLANPACKAGEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanPackageBegin(pArgs->wzPackageId, pArgs->state, pArgs->fCached, pArgs->installCondition, pArgs->repairCondition, pArgs->recommendedState, pArgs->recommendedCacheType, &pResults->requestedState, &pResults->requestedCacheType, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanCompatibleMsiPackageBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_ARGS* pArgs,
+    __inout BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanCompatibleMsiPackageBegin(pArgs->wzPackageId, pArgs->wzCompatiblePackageId, pArgs->wzCompatiblePackageVersion, pArgs->fRecommendedRemove, &pResults->fRequestRemove, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanCompatibleMsiPackageComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_ARGS* pArgs,
+    __inout BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnPlanCompatibleMsiPackageComplete(pArgs->wzPackageId, pArgs->wzCompatiblePackageId, pArgs->hrStatus, pArgs->fRequestedRemove);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanPatchTarget(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANPATCHTARGET_ARGS* pArgs,
+    __inout BA_ONPLANPATCHTARGET_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanPatchTarget(pArgs->wzPackageId, pArgs->wzProductCode, pArgs->recommendedState, &pResults->requestedState, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanMsiFeature(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANMSIFEATURE_ARGS* pArgs,
+    __inout BA_ONPLANMSIFEATURE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanMsiFeature(pArgs->wzPackageId, pArgs->wzFeatureId, pArgs->recommendedState, &pResults->requestedState, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanPackageComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANPACKAGECOMPLETE_ARGS* pArgs,
+    __inout BA_ONPLANPACKAGECOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnPlanPackageComplete(pArgs->wzPackageId, pArgs->hrStatus, pArgs->requested);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlannedCompatiblePackage(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANNEDCOMPATIBLEPACKAGE_ARGS* pArgs,
+    __inout BA_ONPLANNEDCOMPATIBLEPACKAGE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnPlannedCompatiblePackage(pArgs->wzPackageId, pArgs->wzCompatiblePackageId, pArgs->fRemove);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlannedPackage(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANNEDPACKAGE_ARGS* pArgs,
+    __inout BA_ONPLANNEDPACKAGE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnPlannedPackage(pArgs->wzPackageId, pArgs->execute, pArgs->rollback, pArgs->fPlannedCache, pArgs->fPlannedUncache);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnApplyBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONAPPLYBEGIN_ARGS* pArgs,
+    __inout BA_ONAPPLYBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnApplyBegin(pArgs->dwPhaseCount, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnElevateBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONELEVATEBEGIN_ARGS* /*pArgs*/,
+    __inout BA_ONELEVATEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnElevateBegin(&pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnElevateComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONELEVATECOMPLETE_ARGS* pArgs,
+    __inout BA_ONELEVATECOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnElevateComplete(pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnProgress(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPROGRESS_ARGS* pArgs,
+    __inout BA_ONPROGRESS_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnProgress(pArgs->dwProgressPercentage, pArgs->dwOverallPercentage, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnError(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONERROR_ARGS* pArgs,
+    __inout BA_ONERROR_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnError(pArgs->errorType, pArgs->wzPackageId, pArgs->dwCode, pArgs->wzError, pArgs->dwUIHint, pArgs->cData, pArgs->rgwzData, pArgs->nRecommendation, &pResults->nResult);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnRegisterBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONREGISTERBEGIN_ARGS* pArgs,
+    __inout BA_ONREGISTERBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnRegisterBegin(pArgs->recommendedRegistrationType, &pResults->fCancel, &pResults->registrationType);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnRegisterComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONREGISTERCOMPLETE_ARGS* pArgs,
+    __inout BA_ONREGISTERCOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnRegisterComplete(pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEBEGIN_ARGS* /*pArgs*/,
+    __inout BA_ONCACHEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheBegin(&pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCachePackageBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEPACKAGEBEGIN_ARGS* pArgs,
+    __inout BA_ONCACHEPACKAGEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCachePackageBegin(pArgs->wzPackageId, pArgs->cCachePayloads, pArgs->dw64PackageCacheSize, pArgs->fVital, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheAcquireBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEACQUIREBEGIN_ARGS* pArgs,
+    __inout BA_ONCACHEACQUIREBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheAcquireBegin(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->wzSource, pArgs->wzDownloadUrl, pArgs->wzPayloadContainerId, pArgs->recommendation, &pResults->action, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheAcquireProgress(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEACQUIREPROGRESS_ARGS* pArgs,
+    __inout BA_ONCACHEACQUIREPROGRESS_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheAcquireProgress(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->dw64Progress, pArgs->dw64Total, pArgs->dwOverallPercentage, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheAcquireResolving(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEACQUIRERESOLVING_ARGS* pArgs,
+    __inout BA_ONCACHEACQUIRERESOLVING_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheAcquireResolving(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->rgSearchPaths, pArgs->cSearchPaths, pArgs->fFoundLocal, pArgs->dwRecommendedSearchPath, pArgs->wzDownloadUrl, pArgs->wzPayloadContainerId, pArgs->recommendation, &pResults->dwChosenSearchPath, &pResults->action, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheAcquireComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEACQUIRECOMPLETE_ARGS* pArgs,
+    __inout BA_ONCACHEACQUIRECOMPLETE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheAcquireComplete(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->hrStatus, pArgs->recommendation, &pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheVerifyBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEVERIFYBEGIN_ARGS* pArgs,
+    __inout BA_ONCACHEVERIFYBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheVerifyBegin(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheVerifyProgress(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEVERIFYPROGRESS_ARGS* pArgs,
+    __inout BA_ONCACHEVERIFYPROGRESS_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheVerifyProgress(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->dw64Progress, pArgs->dw64Total, pArgs->dwOverallPercentage, pArgs->verifyStep, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheVerifyComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEVERIFYCOMPLETE_ARGS* pArgs,
+    __inout BA_ONCACHEVERIFYCOMPLETE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheVerifyComplete(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->hrStatus, pArgs->recommendation, &pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCachePackageComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEPACKAGECOMPLETE_ARGS* pArgs,
+    __inout BA_ONCACHEPACKAGECOMPLETE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCachePackageComplete(pArgs->wzPackageId, pArgs->hrStatus, pArgs->recommendation, &pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHECOMPLETE_ARGS* pArgs,
+    __inout BA_ONCACHECOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnCacheComplete(pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnExecuteBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONEXECUTEBEGIN_ARGS* pArgs,
+    __inout BA_ONEXECUTEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnExecuteBegin(pArgs->cExecutingPackages, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnExecutePackageBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONEXECUTEPACKAGEBEGIN_ARGS* pArgs,
+    __inout BA_ONEXECUTEPACKAGEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnExecutePackageBegin(pArgs->wzPackageId, pArgs->fExecute, pArgs->action, pArgs->uiLevel, pArgs->fDisableExternalUiHandler, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnExecutePatchTarget(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONEXECUTEPATCHTARGET_ARGS* pArgs,
+    __inout BA_ONEXECUTEPATCHTARGET_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnExecutePatchTarget(pArgs->wzPackageId, pArgs->wzTargetProductCode, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnExecuteProgress(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONEXECUTEPROGRESS_ARGS* pArgs,
+    __inout BA_ONEXECUTEPROGRESS_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnExecuteProgress(pArgs->wzPackageId, pArgs->dwProgressPercentage, pArgs->dwOverallPercentage, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnExecuteMsiMessage(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONEXECUTEMSIMESSAGE_ARGS* pArgs,
+    __inout BA_ONEXECUTEMSIMESSAGE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnExecuteMsiMessage(pArgs->wzPackageId, pArgs->messageType, pArgs->dwUIHint, pArgs->wzMessage, pArgs->cData, pArgs->rgwzData, pArgs->nRecommendation, &pResults->nResult);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnExecuteFilesInUse(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONEXECUTEFILESINUSE_ARGS* pArgs,
+    __inout BA_ONEXECUTEFILESINUSE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnExecuteFilesInUse(pArgs->wzPackageId, pArgs->cFiles, pArgs->rgwzFiles, pArgs->nRecommendation, pArgs->source, &pResults->nResult);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnExecutePackageComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONEXECUTEPACKAGECOMPLETE_ARGS* pArgs,
+    __inout BA_ONEXECUTEPACKAGECOMPLETE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnExecutePackageComplete(pArgs->wzPackageId, pArgs->hrStatus, pArgs->restart, pArgs->recommendation, &pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnExecuteProcessCancel(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONEXECUTEPROCESSCANCEL_ARGS* pArgs,
+    __inout BA_ONEXECUTEPROCESSCANCEL_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnExecuteProcessCancel(pArgs->wzPackageId, pArgs->dwProcessId, pArgs->recommendation, &pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnExecuteComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONEXECUTECOMPLETE_ARGS* pArgs,
+    __inout BA_ONEXECUTECOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnExecuteComplete(pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnUnregisterBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONUNREGISTERBEGIN_ARGS* pArgs,
+    __inout BA_ONUNREGISTERBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnUnregisterBegin(pArgs->recommendedRegistrationType, &pResults->registrationType);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnUnregisterComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONUNREGISTERCOMPLETE_ARGS* pArgs,
+    __inout BA_ONUNREGISTERCOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnUnregisterComplete(pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnApplyComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONAPPLYCOMPLETE_ARGS* pArgs,
+    __inout BA_ONAPPLYCOMPLETE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnApplyComplete(pArgs->hrStatus, pArgs->restart, pArgs->recommendation, &pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnLaunchApprovedExeBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONLAUNCHAPPROVEDEXEBEGIN_ARGS* /*pArgs*/,
+    __inout BA_ONLAUNCHAPPROVEDEXEBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnLaunchApprovedExeBegin(&pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnLaunchApprovedExeComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONLAUNCHAPPROVEDEXECOMPLETE_ARGS* pArgs,
+    __inout BA_ONLAUNCHAPPROVEDEXECOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnLaunchApprovedExeComplete(pArgs->hrStatus, pArgs->dwProcessId);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanMsiPackage(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANMSIPACKAGE_ARGS* pArgs,
+    __inout BA_ONPLANMSIPACKAGE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanMsiPackage(pArgs->wzPackageId, pArgs->fExecute, pArgs->action, pArgs->recommendedFileVersioning, &pResults->fCancel, &pResults->actionMsiProperty, &pResults->uiLevel, &pResults->fDisableExternalUiHandler, &pResults->fileVersioning);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnBeginMsiTransactionBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONBEGINMSITRANSACTIONBEGIN_ARGS* pArgs,
+    __inout BA_ONBEGINMSITRANSACTIONBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnBeginMsiTransactionBegin(pArgs->wzTransactionId, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnBeginMsiTransactionComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONBEGINMSITRANSACTIONCOMPLETE_ARGS* pArgs,
+    __inout BA_ONBEGINMSITRANSACTIONCOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnBeginMsiTransactionComplete(pArgs->wzTransactionId, pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCommitMsiTransactionBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCOMMITMSITRANSACTIONBEGIN_ARGS* pArgs,
+    __inout BA_ONCOMMITMSITRANSACTIONBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCommitMsiTransactionBegin(pArgs->wzTransactionId, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCommitMsiTransactionComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCOMMITMSITRANSACTIONCOMPLETE_ARGS* pArgs,
+    __inout BA_ONCOMMITMSITRANSACTIONCOMPLETE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCommitMsiTransactionComplete(pArgs->wzTransactionId, pArgs->hrStatus, pArgs->restart, pArgs->recommendation, &pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnRollbackMsiTransactionBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONROLLBACKMSITRANSACTIONBEGIN_ARGS* pArgs,
+    __inout BA_ONROLLBACKMSITRANSACTIONBEGIN_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnRollbackMsiTransactionBegin(pArgs->wzTransactionId);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnRollbackMsiTransactionComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONROLLBACKMSITRANSACTIONCOMPLETE_ARGS* pArgs,
+    __inout BA_ONROLLBACKMSITRANSACTIONCOMPLETE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnRollbackMsiTransactionComplete(pArgs->wzTransactionId, pArgs->hrStatus, pArgs->restart, pArgs->recommendation, &pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPauseAutomaticUpdatesBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPAUSEAUTOMATICUPDATESBEGIN_ARGS* /*pArgs*/,
+    __inout BA_ONPAUSEAUTOMATICUPDATESBEGIN_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnPauseAutomaticUpdatesBegin();
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPauseAutomaticUpdatesComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_ARGS* pArgs,
+    __inout BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnPauseAutomaticUpdatesComplete(pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnSystemRestorePointBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONSYSTEMRESTOREPOINTBEGIN_ARGS* /*pArgs*/,
+    __inout BA_ONSYSTEMRESTOREPOINTBEGIN_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnSystemRestorePointBegin();
+}
+
+static HRESULT BalBaseBAFunctionsProcOnSystemRestorePointComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONSYSTEMRESTOREPOINTCOMPLETE_ARGS* pArgs,
+    __inout BA_ONSYSTEMRESTOREPOINTCOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnSystemRestorePointComplete(pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanForwardCompatibleBundle(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANFORWARDCOMPATIBLEBUNDLE_ARGS* pArgs,
+    __inout BA_ONPLANFORWARDCOMPATIBLEBUNDLE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanForwardCompatibleBundle(pArgs->wzBundleId, pArgs->relationType, pArgs->wzBundleTag, pArgs->fPerMachine, pArgs->wzVersion, pArgs->fRecommendedIgnoreBundle, &pResults->fCancel, &pResults->fIgnoreBundle);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheContainerOrPayloadVerifyBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_ARGS* pArgs,
+    __inout BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheContainerOrPayloadVerifyBegin(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheContainerOrPayloadVerifyProgress(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_ARGS* pArgs,
+    __inout BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCacheContainerOrPayloadVerifyProgress(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->dw64Progress, pArgs->dw64Total, pArgs->dwOverallPercentage, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCacheContainerOrPayloadVerifyComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_ARGS* pArgs,
+    __inout BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnCacheContainerOrPayloadVerifyComplete(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCachePayloadExtractBegin(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEPAYLOADEXTRACTBEGIN_ARGS* pArgs,
+    __inout BA_ONCACHEPAYLOADEXTRACTBEGIN_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCachePayloadExtractBegin(pArgs->wzContainerId, pArgs->wzPayloadId, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCachePayloadExtractProgress(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEPAYLOADEXTRACTPROGRESS_ARGS* pArgs,
+    __inout BA_ONCACHEPAYLOADEXTRACTPROGRESS_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCachePayloadExtractProgress(pArgs->wzContainerId, pArgs->wzPayloadId, pArgs->dw64Progress, pArgs->dw64Total, pArgs->dwOverallPercentage, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCachePayloadExtractComplete(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEPAYLOADEXTRACTCOMPLETE_ARGS* pArgs,
+    __inout BA_ONCACHEPAYLOADEXTRACTCOMPLETE_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnCachePayloadExtractComplete(pArgs->wzContainerId, pArgs->wzPayloadId, pArgs->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanRestoreRelatedBundle(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANRESTORERELATEDBUNDLE_ARGS* pArgs,
+    __inout BA_ONPLANRESTORERELATEDBUNDLE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanRestoreRelatedBundle(pArgs->wzBundleId, pArgs->recommendedState, &pResults->requestedState, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnPlanRelatedBundleType(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONPLANRELATEDBUNDLETYPE_ARGS* pArgs,
+    __inout BA_ONPLANRELATEDBUNDLETYPE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnPlanRelatedBundleType(pArgs->wzBundleId, pArgs->recommendedType, &pResults->requestedType, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnApplyDowngrade(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONAPPLYDOWNGRADE_ARGS* pArgs,
+    __inout BA_ONAPPLYDOWNGRADE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnApplyDowngrade(pArgs->hrRecommended, &pResults->hrStatus);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnDetectRelatedBundlePackage(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONDETECTRELATEDBUNDLEPACKAGE_ARGS* pArgs,
+    __inout BA_ONDETECTRELATEDBUNDLEPACKAGE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnDetectRelatedBundlePackage(pArgs->wzPackageId, pArgs->wzBundleId, pArgs->relationType, pArgs->fPerMachine, pArgs->wzVersion, &pResults->fCancel);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnCachePackageNonVitalValidationFailure(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_ARGS* pArgs,
+    __inout BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnCachePackageNonVitalValidationFailure(pArgs->wzPackageId, pArgs->hrStatus, pArgs->recommendation, &pResults->action);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnThemeLoaded(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_FUNCTIONS_ONTHEMELOADED_ARGS* pArgs,
+    __inout BA_FUNCTIONS_ONTHEMELOADED_RESULTS* /*pResults*/
+    )
+{
+    return pBAFunctions->OnThemeLoaded(pArgs->hWnd);
+}
+
+static HRESULT BalBaseBAFunctionsProcWndProc(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_FUNCTIONS_WNDPROC_ARGS* pArgs,
+    __inout BA_FUNCTIONS_WNDPROC_RESULTS* pResults
+    )
+{
+    return pBAFunctions->WndProc(pArgs->hWnd, pArgs->uMsg, pArgs->wParam, pArgs->lParam, &pResults->fProcessed, &pResults->lResult);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnThemeControlLoading(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_FUNCTIONS_ONTHEMECONTROLLOADING_ARGS* pArgs,
+    __inout BA_FUNCTIONS_ONTHEMECONTROLLOADING_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnThemeControlLoading(pArgs->wzName, &pResults->fProcessed, &pResults->wId, &pResults->dwAutomaticBehaviorType);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnThemeControlWmCommand(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_FUNCTIONS_ONTHEMECONTROLWMCOMMAND_ARGS* pArgs,
+    __inout BA_FUNCTIONS_ONTHEMECONTROLWMCOMMAND_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnThemeControlWmCommand(pArgs->wParam, pArgs->wzName, pArgs->wId, pArgs->hWnd, &pResults->fProcessed, &pResults->lResult);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnThemeControlWmNotify(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_FUNCTIONS_ONTHEMECONTROLWMNOTIFY_ARGS* pArgs,
+    __inout BA_FUNCTIONS_ONTHEMECONTROLWMNOTIFY_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnThemeControlWmNotify(pArgs->lParam, pArgs->wzName, pArgs->wId, pArgs->hWnd, &pResults->fProcessed, &pResults->lResult);
+}
+
+static HRESULT BalBaseBAFunctionsProcOnThemeControlLoaded(
+    __in IBAFunctions* pBAFunctions,
+    __in BA_FUNCTIONS_ONTHEMECONTROLLOADED_ARGS* pArgs,
+    __inout BA_FUNCTIONS_ONTHEMECONTROLLOADED_RESULTS* pResults
+    )
+{
+    return pBAFunctions->OnThemeControlLoaded(pArgs->wzName, pArgs->wId, pArgs->hWnd, &pResults->fProcessed);
+}
+
+/*******************************************************************
+BalBaseBAFunctionsProc - requires pvContext to be of type IBAFunctions.
+Provides a default mapping between the message based BAFunctions interface and
+the COM-based BAFunctions interface.
+
+*******************************************************************/
+HRESULT WINAPI BalBaseBAFunctionsProc(
+    __in BA_FUNCTIONS_MESSAGE message,
+    __in const LPVOID pvArgs,
+    __inout LPVOID pvResults,
+    __in_opt LPVOID pvContext
+    )
+{
+    IBAFunctions* pBAFunctions = reinterpret_cast<IBAFunctions*>(pvContext);
+    HRESULT hr = pBAFunctions->BAFunctionsProc(message, pvArgs, pvResults, pvContext);
+
+    if (E_NOTIMPL == hr)
+    {
+        switch (message)
+        {
+        case BA_FUNCTIONS_MESSAGE_ONCREATE:
+            // ONCREATE is handled when the function is created, not via callback.
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDESTROY:
+            hr = BalBaseBAFunctionsProcOnDestroy(pBAFunctions, reinterpret_cast<BA_ONDESTROY_ARGS*>(pvArgs), reinterpret_cast<BA_ONDESTROY_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONSTARTUP:
+            hr = BalBaseBAFunctionsProcOnStartup(pBAFunctions, reinterpret_cast<BA_ONSTARTUP_ARGS*>(pvArgs), reinterpret_cast<BA_ONSTARTUP_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONSHUTDOWN:
+            hr = BalBaseBAFunctionsProcOnShutdown(pBAFunctions, reinterpret_cast<BA_ONSHUTDOWN_ARGS*>(pvArgs), reinterpret_cast<BA_ONSHUTDOWN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTBEGIN:
+            hr = BalBaseBAFunctionsProcOnDetectBegin(pBAFunctions, reinterpret_cast<BA_ONDETECTBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnDetectComplete(pBAFunctions, reinterpret_cast<BA_ONDETECTCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANBEGIN:
+            hr = BalBaseBAFunctionsProcOnPlanBegin(pBAFunctions, reinterpret_cast<BA_ONPLANBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnPlanComplete(pBAFunctions, reinterpret_cast<BA_ONPLANCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTFORWARDCOMPATIBLEBUNDLE:
+            hr = BalBaseBAFunctionsProcOnDetectForwardCompatibleBundle(pBAFunctions, reinterpret_cast<BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTUPDATEBEGIN:
+            hr = BalBaseBAFunctionsProcOnDetectUpdateBegin(pBAFunctions, reinterpret_cast<BA_ONDETECTUPDATEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTUPDATEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTUPDATE:
+            hr = BalBaseBAFunctionsProcOnDetectUpdate(pBAFunctions, reinterpret_cast<BA_ONDETECTUPDATE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTUPDATE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTUPDATECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnDetectUpdateComplete(pBAFunctions, reinterpret_cast<BA_ONDETECTUPDATECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTUPDATECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTRELATEDBUNDLE:
+            hr = BalBaseBAFunctionsProcOnDetectRelatedBundle(pBAFunctions, reinterpret_cast<BA_ONDETECTRELATEDBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTRELATEDBUNDLE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTPACKAGEBEGIN:
+            hr = BalBaseBAFunctionsProcOnDetectPackageBegin(pBAFunctions, reinterpret_cast<BA_ONDETECTPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTPACKAGEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTRELATEDMSIPACKAGE:
+            hr = BalBaseBAFunctionsProcOnDetectRelatedMsiPackage(pBAFunctions, reinterpret_cast<BA_ONDETECTRELATEDMSIPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTRELATEDMSIPACKAGE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTPATCHTARGET:
+            hr = BalBaseBAFunctionsProcOnDetectPatchTarget(pBAFunctions, reinterpret_cast<BA_ONDETECTPATCHTARGET_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTPATCHTARGET_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTMSIFEATURE:
+            hr = BalBaseBAFunctionsProcOnDetectMsiFeature(pBAFunctions, reinterpret_cast<BA_ONDETECTMSIFEATURE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTMSIFEATURE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTPACKAGECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnDetectPackageComplete(pBAFunctions, reinterpret_cast<BA_ONDETECTPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTPACKAGECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANRELATEDBUNDLE:
+            hr = BalBaseBAFunctionsProcOnPlanRelatedBundle(pBAFunctions, reinterpret_cast<BA_ONPLANRELATEDBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANRELATEDBUNDLE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANPACKAGEBEGIN:
+            hr = BalBaseBAFunctionsProcOnPlanPackageBegin(pBAFunctions, reinterpret_cast<BA_ONPLANPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANPACKAGEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANPATCHTARGET:
+            hr = BalBaseBAFunctionsProcOnPlanPatchTarget(pBAFunctions, reinterpret_cast<BA_ONPLANPATCHTARGET_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANPATCHTARGET_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANMSIFEATURE:
+            hr = BalBaseBAFunctionsProcOnPlanMsiFeature(pBAFunctions, reinterpret_cast<BA_ONPLANMSIFEATURE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANMSIFEATURE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANPACKAGECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnPlanPackageComplete(pBAFunctions, reinterpret_cast<BA_ONPLANPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANPACKAGECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONAPPLYBEGIN:
+            hr = BalBaseBAFunctionsProcOnApplyBegin(pBAFunctions, reinterpret_cast<BA_ONAPPLYBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONAPPLYBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONELEVATEBEGIN:
+            hr = BalBaseBAFunctionsProcOnElevateBegin(pBAFunctions, reinterpret_cast<BA_ONELEVATEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONELEVATEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONELEVATECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnElevateComplete(pBAFunctions, reinterpret_cast<BA_ONELEVATECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONELEVATECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPROGRESS:
+            hr = BalBaseBAFunctionsProcOnProgress(pBAFunctions, reinterpret_cast<BA_ONPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONPROGRESS_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONERROR:
+            hr = BalBaseBAFunctionsProcOnError(pBAFunctions, reinterpret_cast<BA_ONERROR_ARGS*>(pvArgs), reinterpret_cast<BA_ONERROR_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONREGISTERBEGIN:
+            hr = BalBaseBAFunctionsProcOnRegisterBegin(pBAFunctions, reinterpret_cast<BA_ONREGISTERBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONREGISTERBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONREGISTERCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnRegisterComplete(pBAFunctions, reinterpret_cast<BA_ONREGISTERCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONREGISTERCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEBEGIN:
+            hr = BalBaseBAFunctionsProcOnCacheBegin(pBAFunctions, reinterpret_cast<BA_ONCACHEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEPACKAGEBEGIN:
+            hr = BalBaseBAFunctionsProcOnCachePackageBegin(pBAFunctions, reinterpret_cast<BA_ONCACHEPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPACKAGEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEACQUIREBEGIN:
+            hr = BalBaseBAFunctionsProcOnCacheAcquireBegin(pBAFunctions, reinterpret_cast<BA_ONCACHEACQUIREBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEACQUIREBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEACQUIREPROGRESS:
+            hr = BalBaseBAFunctionsProcOnCacheAcquireProgress(pBAFunctions, reinterpret_cast<BA_ONCACHEACQUIREPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEACQUIREPROGRESS_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEACQUIRERESOLVING:
+            hr = BalBaseBAFunctionsProcOnCacheAcquireResolving(pBAFunctions, reinterpret_cast<BA_ONCACHEACQUIRERESOLVING_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEACQUIRERESOLVING_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEACQUIRECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnCacheAcquireComplete(pBAFunctions, reinterpret_cast<BA_ONCACHEACQUIRECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEACQUIRECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEVERIFYBEGIN:
+            hr = BalBaseBAFunctionsProcOnCacheVerifyBegin(pBAFunctions, reinterpret_cast<BA_ONCACHEVERIFYBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEVERIFYBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEVERIFYPROGRESS:
+            hr = BalBaseBAFunctionsProcOnCacheVerifyProgress(pBAFunctions, reinterpret_cast<BA_ONCACHEVERIFYPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEVERIFYPROGRESS_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEVERIFYCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnCacheVerifyComplete(pBAFunctions, reinterpret_cast<BA_ONCACHEVERIFYCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEVERIFYCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEPACKAGECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnCachePackageComplete(pBAFunctions, reinterpret_cast<BA_ONCACHEPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPACKAGECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnCacheComplete(pBAFunctions, reinterpret_cast<BA_ONCACHECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONEXECUTEBEGIN:
+            hr = BalBaseBAFunctionsProcOnExecuteBegin(pBAFunctions, reinterpret_cast<BA_ONEXECUTEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPACKAGEBEGIN:
+            hr = BalBaseBAFunctionsProcOnExecutePackageBegin(pBAFunctions, reinterpret_cast<BA_ONEXECUTEPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPACKAGEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPATCHTARGET:
+            hr = BalBaseBAFunctionsProcOnExecutePatchTarget(pBAFunctions, reinterpret_cast<BA_ONEXECUTEPATCHTARGET_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPATCHTARGET_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPROGRESS:
+            hr = BalBaseBAFunctionsProcOnExecuteProgress(pBAFunctions, reinterpret_cast<BA_ONEXECUTEPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPROGRESS_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONEXECUTEMSIMESSAGE:
+            hr = BalBaseBAFunctionsProcOnExecuteMsiMessage(pBAFunctions, reinterpret_cast<BA_ONEXECUTEMSIMESSAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEMSIMESSAGE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONEXECUTEFILESINUSE:
+            hr = BalBaseBAFunctionsProcOnExecuteFilesInUse(pBAFunctions, reinterpret_cast<BA_ONEXECUTEFILESINUSE_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEFILESINUSE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPACKAGECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnExecutePackageComplete(pBAFunctions, reinterpret_cast<BA_ONEXECUTEPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPACKAGECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONEXECUTECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnExecuteComplete(pBAFunctions, reinterpret_cast<BA_ONEXECUTECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONUNREGISTERBEGIN:
+            hr = BalBaseBAFunctionsProcOnUnregisterBegin(pBAFunctions, reinterpret_cast<BA_ONUNREGISTERBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONUNREGISTERBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONUNREGISTERCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnUnregisterComplete(pBAFunctions, reinterpret_cast<BA_ONUNREGISTERCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONUNREGISTERCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONAPPLYCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnApplyComplete(pBAFunctions, reinterpret_cast<BA_ONAPPLYCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONAPPLYCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONLAUNCHAPPROVEDEXEBEGIN:
+            hr = BalBaseBAFunctionsProcOnLaunchApprovedExeBegin(pBAFunctions, reinterpret_cast<BA_ONLAUNCHAPPROVEDEXEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONLAUNCHAPPROVEDEXEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONLAUNCHAPPROVEDEXECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnLaunchApprovedExeComplete(pBAFunctions, reinterpret_cast<BA_ONLAUNCHAPPROVEDEXECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONLAUNCHAPPROVEDEXECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANMSIPACKAGE:
+            hr = BalBaseBAFunctionsProcOnPlanMsiPackage(pBAFunctions, reinterpret_cast<BA_ONPLANMSIPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANMSIPACKAGE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONBEGINMSITRANSACTIONBEGIN:
+            hr = BalBaseBAFunctionsProcOnBeginMsiTransactionBegin(pBAFunctions, reinterpret_cast<BA_ONBEGINMSITRANSACTIONBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONBEGINMSITRANSACTIONBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONBEGINMSITRANSACTIONCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnBeginMsiTransactionComplete(pBAFunctions, reinterpret_cast<BA_ONBEGINMSITRANSACTIONCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONBEGINMSITRANSACTIONCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCOMMITMSITRANSACTIONBEGIN:
+            hr = BalBaseBAFunctionsProcOnCommitMsiTransactionBegin(pBAFunctions, reinterpret_cast<BA_ONCOMMITMSITRANSACTIONBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCOMMITMSITRANSACTIONBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCOMMITMSITRANSACTIONCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnCommitMsiTransactionComplete(pBAFunctions, reinterpret_cast<BA_ONCOMMITMSITRANSACTIONCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCOMMITMSITRANSACTIONCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONROLLBACKMSITRANSACTIONBEGIN:
+            hr = BalBaseBAFunctionsProcOnRollbackMsiTransactionBegin(pBAFunctions, reinterpret_cast<BA_ONROLLBACKMSITRANSACTIONBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONROLLBACKMSITRANSACTIONBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONROLLBACKMSITRANSACTIONCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnRollbackMsiTransactionComplete(pBAFunctions, reinterpret_cast<BA_ONROLLBACKMSITRANSACTIONCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONROLLBACKMSITRANSACTIONCOMPLETE_RESULTS*>(pvResults));
+        case BA_FUNCTIONS_MESSAGE_ONPAUSEAUTOMATICUPDATESBEGIN:
+            hr = BalBaseBAFunctionsProcOnPauseAutomaticUpdatesBegin(pBAFunctions, reinterpret_cast<BA_ONPAUSEAUTOMATICUPDATESBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONPAUSEAUTOMATICUPDATESBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPAUSEAUTOMATICUPDATESCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnPauseAutomaticUpdatesComplete(pBAFunctions, reinterpret_cast<BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONSYSTEMRESTOREPOINTBEGIN:
+            hr = BalBaseBAFunctionsProcOnSystemRestorePointBegin(pBAFunctions, reinterpret_cast<BA_ONSYSTEMRESTOREPOINTBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONSYSTEMRESTOREPOINTBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONSYSTEMRESTOREPOINTCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnSystemRestorePointComplete(pBAFunctions, reinterpret_cast<BA_ONSYSTEMRESTOREPOINTCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONSYSTEMRESTOREPOINTCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANNEDPACKAGE:
+            hr = BalBaseBAFunctionsProcOnPlannedPackage(pBAFunctions, reinterpret_cast<BA_ONPLANNEDPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANNEDPACKAGE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANFORWARDCOMPATIBLEBUNDLE:
+            hr = BalBaseBAFunctionsProcOnPlanForwardCompatibleBundle(pBAFunctions, reinterpret_cast<BA_ONPLANFORWARDCOMPATIBLEBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANFORWARDCOMPATIBLEBUNDLE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYBEGIN:
+            hr = BalBaseBAFunctionsProcOnCacheContainerOrPayloadVerifyBegin(pBAFunctions, reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS:
+            hr = BalBaseBAFunctionsProcOnCacheContainerOrPayloadVerifyProgress(pBAFunctions, reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnCacheContainerOrPayloadVerifyComplete(pBAFunctions, reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEPAYLOADEXTRACTBEGIN:
+            hr = BalBaseBAFunctionsProcOnCachePayloadExtractBegin(pBAFunctions, reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEPAYLOADEXTRACTPROGRESS:
+            hr = BalBaseBAFunctionsProcOnCachePayloadExtractProgress(pBAFunctions, reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTPROGRESS_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEPAYLOADEXTRACTCOMPLETE:
+            hr = BalBaseBAFunctionsProcOnCachePayloadExtractComplete(pBAFunctions, reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTCOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANROLLBACKBOUNDARY:
+            hr = BalBaseBAFunctionsProcOnPlanRollbackBoundary(pBAFunctions, reinterpret_cast<BA_ONPLANROLLBACKBOUNDARY_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANROLLBACKBOUNDARY_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTCOMPATIBLEMSIPACKAGE:
+            hr = BalBaseBAFunctionsProcOnDetectCompatiblePackage(pBAFunctions, reinterpret_cast<BA_ONDETECTCOMPATIBLEMSIPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTCOMPATIBLEMSIPACKAGE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGEBEGIN:
+            hr = BalBaseBAFunctionsProcOnPlanCompatibleMsiPackageBegin(pBAFunctions, reinterpret_cast<BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE:
+            hr = BalBaseBAFunctionsProcOnPlanCompatibleMsiPackageComplete(pBAFunctions, reinterpret_cast<BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE:
+            hr = BalBaseBAFunctionsProcOnPlannedCompatiblePackage(pBAFunctions, reinterpret_cast<BA_ONPLANNEDCOMPATIBLEPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANNEDCOMPATIBLEPACKAGE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANRESTORERELATEDBUNDLE:
+            hr = BalBaseBAFunctionsProcOnPlanRestoreRelatedBundle(pBAFunctions, reinterpret_cast<BA_ONPLANRESTORERELATEDBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANRESTORERELATEDBUNDLE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONPLANRELATEDBUNDLETYPE:
+            hr = BalBaseBAFunctionsProcOnPlanRelatedBundleType(pBAFunctions, reinterpret_cast<BA_ONPLANRELATEDBUNDLETYPE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANRELATEDBUNDLETYPE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONAPPLYDOWNGRADE:
+            hr = BalBaseBAFunctionsProcOnApplyDowngrade(pBAFunctions, reinterpret_cast<BA_ONAPPLYDOWNGRADE_ARGS*>(pvArgs), reinterpret_cast<BA_ONAPPLYDOWNGRADE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPROCESSCANCEL:
+            hr = BalBaseBAFunctionsProcOnExecuteProcessCancel(pBAFunctions, reinterpret_cast<BA_ONEXECUTEPROCESSCANCEL_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPROCESSCANCEL_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONDETECTRELATEDBUNDLEPACKAGE:
+            hr = BalBaseBAFunctionsProcOnDetectRelatedBundlePackage(pBAFunctions, reinterpret_cast<BA_ONDETECTRELATEDBUNDLEPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTRELATEDBUNDLEPACKAGE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONCACHEPACKAGENONVITALVALIDATIONFAILURE:
+            hr = BalBaseBAFunctionsProcOnCachePackageNonVitalValidationFailure(pBAFunctions, reinterpret_cast<BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONTHEMELOADED:
+            hr = BalBaseBAFunctionsProcOnThemeLoaded(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMELOADED_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMELOADED_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_WNDPROC:
+            hr = BalBaseBAFunctionsProcWndProc(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_WNDPROC_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_WNDPROC_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONTHEMECONTROLLOADING:
+            hr = BalBaseBAFunctionsProcOnThemeControlLoading(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLLOADING_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLLOADING_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONTHEMECONTROLWMCOMMAND:
+            hr = BalBaseBAFunctionsProcOnThemeControlWmCommand(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLWMCOMMAND_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLWMCOMMAND_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONTHEMECONTROLWMNOTIFY:
+            hr = BalBaseBAFunctionsProcOnThemeControlWmNotify(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLWMNOTIFY_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLWMNOTIFY_RESULTS*>(pvResults));
+            break;
+        case BA_FUNCTIONS_MESSAGE_ONTHEMECONTROLLOADED:
+            hr = BalBaseBAFunctionsProcOnThemeControlLoaded(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLLOADED_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLLOADED_RESULTS*>(pvResults));
+            break;
+        }
+    }
+
+    return hr;
+}
diff --git a/src/api/burn/balutil/BalBootstrapperEngine.cpp b/src/api/burn/balutil/BalBootstrapperEngine.cpp
index be53c6b9..b924906e 100644
--- a/src/api/burn/balutil/BalBootstrapperEngine.cpp
+++ b/src/api/burn/balutil/BalBootstrapperEngine.cpp
@@ -2,7 +2,6 @@
 
 #include "precomp.h"
 
-
 class CBalBootstrapperEngine : public IBootstrapperEngine
 {
 public: // IUnknown
@@ -64,18 +63,44 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETPACKAGECOUNT_ARGS args = { };
         BAENGINE_GETPACKAGECOUNT_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
         ExitOnNull(pcPackages, hr, E_INVALIDARG, "pcPackages is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetPackageCount args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetPackageCount results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETPACKAGECOUNT, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetPackageCount failed.");
 
-        results.cbSize = sizeof(results);
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetPackageCount results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETPACKAGECOUNT, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, (DWORD*)&results.cPackages);
+        ExitOnFailure(hr, "Failed to read value length from GetPackageCount results.");
 
         *pcPackages = results.cPackages;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -87,20 +112,50 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETVARIABLENUMERIC_ARGS args = { };
         BAENGINE_GETVARIABLENUMERIC_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczValue = NULL;
 
         ExitOnNull(pllValue, hr, E_INVALIDARG, "pllValue is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableNumeric args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable name of GetVariableNumeric args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableNumeric results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLENUMERIC, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLENUMERIC, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetVariableNumeric failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableNumeric results.");
+
+        hr = BuffReadNumber64(rpc.pbData, rpc.cbData, &iBuffer, (DWORD64*)&results.llValue);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableNumeric results.");
 
         *pllValue = results.llValue;
 
     LExit:
-        SecureZeroMemory(&results, sizeof(results));
+        ReleaseStr(sczValue);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -113,21 +168,69 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETVARIABLESTRING_ARGS args = { };
         BAENGINE_GETVARIABLESTRING_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczValue = NULL;
 
         ExitOnNull(pcchValue, hr, E_INVALIDARG, "pcchValue is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
 
-        results.cbSize = sizeof(results);
-        results.wzValue = wzValue;
-        results.cchValue = *pcchValue;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        results.cchValue = static_cast<DWORD>(*pcchValue);
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableString args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable name of GetVariableString args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableString results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchValue);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableString results value.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLESTRING, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetVariableString failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableString results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLESTRING, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchValue);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableString results.");
+
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczValue);
+        ExitOnFailure(hr, "Failed to read value from GetVariableString results.");
+
+        results.wzValue = sczValue;
+
+        if (wzValue)
+        {
+            hr = ::StringCchCopyW(wzValue, *pcchValue, results.wzValue);
+        }
+        else if (results.cchValue)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchValue = results.cchValue;
+        ExitOnFailure(hr, "Failed to copy value from GetVariableString results.");
 
     LExit:
+        ReleaseStr(sczValue);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -140,21 +243,70 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETVARIABLEVERSION_ARGS args = { };
         BAENGINE_GETVARIABLEVERSION_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczValue = NULL;
 
         ExitOnNull(pcchValue, hr, E_INVALIDARG, "pcchValue is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
 
-        results.cbSize = sizeof(results);
-        results.wzValue = wzValue;
-        results.cchValue = *pcchValue;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        hr = DutilSizetToDword(*pcchValue, &results.cchValue);
+        ExitOnFailure(hr, "Failed to convert pcchValue to DWORD.");
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableVersion args.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLEVERSION, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable name of GetVariableVersion args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableVersion results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchValue);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableVersion results value.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLEVERSION, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetVariableVersion failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableVersion results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchValue);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableVersion results.");
+
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczValue);
+        ExitOnFailure(hr, "Failed to read value from GetVariableVersion results.");
+
+        results.wzValue = sczValue;
+
+        if (wzValue)
+        {
+            hr = ::StringCchCopyW(wzValue, *pcchValue, results.wzValue);
+        }
+        else if (results.cchValue)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchValue = results.cchValue;
+        ExitOnFailure(hr, "Failed to copy value from GetVariableVersion results.");
 
     LExit:
+        ReleaseStr(sczValue);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -168,21 +320,74 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETRELATEDBUNDLEVARIABLE_ARGS args = { };
         BAENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczValue = NULL;
 
         ExitOnNull(pcchValue, hr, E_INVALIDARG, "pcchValue is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzBundleId = wzBundleId;
         args.wzVariable = wzVariable;
 
-        results.cbSize = sizeof(results);
-        results.wzValue = wzValue;
-        results.cchValue = *pcchValue;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        hr = DutilSizetToDword(*pcchValue, &results.cchValue);
+        ExitOnFailure(hr, "Failed to convert pcchValue to DWORD.");
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetRelatedBundleVariable args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzBundleId);
+        ExitOnFailure(hr, "Failed to write bundle id of GetRelatedBundleVariable args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable name of GetRelatedBundleVariable args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetRelatedBundleVariable results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchValue);
+        ExitOnFailure(hr, "Failed to write API version of GetRelatedBundleVariable results value.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetRelatedBundleVariable failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetRelatedBundleVariable results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchValue);
+        ExitOnFailure(hr, "Failed to read value length from GetRelatedBundleVariable results.");
+
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczValue);
+        ExitOnFailure(hr, "Failed to read value from GetRelatedBundleVariable results.");
+
+        results.wzValue = sczValue;
+
+        if (wzValue)
+        {
+            hr = ::StringCchCopyW(wzValue, *pcchValue, results.wzValue);
+        }
+        else if (results.cchValue)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchValue = results.cchValue;
+        ExitOnFailure(hr, "Failed to copy value from GetRelatedBundleVariable results.");
+
     LExit:
+        ReleaseStr(sczValue);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -195,21 +400,70 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_FORMATSTRING_ARGS args = { };
         BAENGINE_FORMATSTRING_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczOut = NULL;
 
         ExitOnNull(pcchOut, hr, E_INVALIDARG, "pcchOut is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzIn = wzIn;
 
-        results.cbSize = sizeof(results);
-        results.wzOut = wzOut;
-        results.cchOut = *pcchOut;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        hr = DutilSizetToDword(*pcchOut, &results.cchOut);
+        ExitOnFailure(hr, "Failed to convert pcchOut to DWORD.");
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of FormatString args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzIn);
+        ExitOnFailure(hr, "Failed to write string to format of FormatString args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of FormatString results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchOut);
+        ExitOnFailure(hr, "Failed to write format string maximum size of FormatString results value.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_FORMATSTRING, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA FormatString failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from FormatString results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchOut);
+        ExitOnFailure(hr, "Failed to read formatted string length from FormatString results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_FORMATSTRING, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczOut);
+        ExitOnFailure(hr, "Failed to read formatted string from FormatString results.");
+
+        results.wzOut = sczOut;
+
+        if (wzOut)
+        {
+            hr = ::StringCchCopyW(wzOut, *pcchOut, results.wzOut);
+        }
+        else if (results.cchOut)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchOut = results.cchOut;
+        ExitOnFailure(hr, "Failed to copy formatted string from FormatString results.");
 
     LExit:
+        ReleaseStr(sczOut);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -222,21 +476,70 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_ESCAPESTRING_ARGS args = { };
         BAENGINE_ESCAPESTRING_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczOut = NULL;
 
         ExitOnNull(pcchOut, hr, E_INVALIDARG, "pcchOut is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzIn = wzIn;
 
-        results.cbSize = sizeof(results);
-        results.wzOut = wzOut;
-        results.cchOut = *pcchOut;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        hr = DutilSizetToDword(*pcchOut, &results.cchOut);
+        ExitOnFailure(hr, "Failed to convert pcchOut to DWORD.");
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of EscapeString args.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_ESCAPESTRING, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzIn);
+        ExitOnFailure(hr, "Failed to write string to escape of EscapeString args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of EscapeString results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchOut);
+        ExitOnFailure(hr, "Failed to write escape string maximum size of EscapeString results value.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_ESCAPESTRING, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA EscapeString failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from EscapeString results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchOut);
+        ExitOnFailure(hr, "Failed to read escaped string length from EscapeString results.");
+
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczOut);
+        ExitOnFailure(hr, "Failed to read escaped string from EscapeString results.");
+
+        results.wzOut = sczOut;
+
+        if (wzOut)
+        {
+            hr = ::StringCchCopyW(wzOut, *pcchOut, results.wzOut);
+        }
+        else if (results.cchOut)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchOut = results.cchOut;
+        ExitOnFailure(hr, "Failed to copy escaped string from EscapeString results.");
 
     LExit:
+        ReleaseStr(sczOut);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -248,19 +551,56 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_EVALUATECONDITION_ARGS args = { };
         BAENGINE_EVALUATECONDITION_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
+        ExitOnNull(wzCondition, hr, E_INVALIDARG, "wzCondition is required");
         ExitOnNull(pf, hr, E_INVALIDARG, "pf is required");
 
-        args.cbSize = sizeof(args);
+        // Empty condition evaluates to true.
+        if (!*wzCondition)
+        {
+            *pf = TRUE;
+            ExitFunction();
+        }
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzCondition = wzCondition;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of EvaluateCondition args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzCondition);
+        ExitOnFailure(hr, "Failed to write condition of EvaluateCondition args.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_EVALUATECONDITION, &args, &results, m_pvBAEngineProcContext);
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of EvaluateCondition results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_EVALUATECONDITION, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA EvaluateCondition failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from EvaluateCondition results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, reinterpret_cast<DWORD*>(&results.f));
+        ExitOnFailure(hr, "Failed to read result from EvaluateCondition results.");
 
         *pf = results.f;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -269,16 +609,44 @@ public: // IBootstrapperEngine
         __in_z LPCWSTR wzMessage
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_LOG_ARGS args = { };
         BAENGINE_LOG_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.level = level;
         args.wzMessage = wzMessage;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Log args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.level);
+        ExitOnFailure(hr, "Failed to write level of Log args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzMessage);
+        ExitOnFailure(hr, "Failed to write message of Log args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Log results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_LOG, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_LOG, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Log failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SendEmbeddedError(
@@ -291,21 +659,56 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_SENDEMBEDDEDERROR_ARGS args = { };
         BAENGINE_SENDEMBEDDEDERROR_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
         ExitOnNull(pnResult, hr, E_INVALIDARG, "pnResult is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.dwErrorCode = dwErrorCode;
         args.wzMessage = wzMessage;
         args.dwUIHint = dwUIHint;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SendEmbeddedError args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwErrorCode);
+        ExitOnFailure(hr, "Failed to write error code of SendEmbeddedError args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzMessage);
+        ExitOnFailure(hr, "Failed to write message of SendEmbeddedError args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwUIHint);
+        ExitOnFailure(hr, "Failed to write UI hint of SendEmbeddedError args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SendEmbeddedError results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SENDEMBEDDEDERROR, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SENDEMBEDDEDERROR, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SendEmbeddedError failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from SendEmbeddedError results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, reinterpret_cast<DWORD*>(&results.nResult));
+        ExitOnFailure(hr, "Failed to read result from SendEmbeddedError results.");
 
         *pnResult = results.nResult;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -318,20 +721,52 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_SENDEMBEDDEDPROGRESS_ARGS args = { };
         BAENGINE_SENDEMBEDDEDPROGRESS_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
         ExitOnNull(pnResult, hr, E_INVALIDARG, "pnResult is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.dwProgressPercentage = dwProgressPercentage;
         args.dwOverallProgressPercentage = dwOverallProgressPercentage;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SendEmbeddedProgress args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwProgressPercentage);
+        ExitOnFailure(hr, "Failed to write progress of SendEmbeddedProgress args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwOverallProgressPercentage);
+        ExitOnFailure(hr, "Failed to write overall progress of SendEmbeddedProgress args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SendEmbeddedProgress results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SENDEMBEDDEDPROGRESS, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SendEmbeddedProgress failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from SendEmbeddedProgress results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SENDEMBEDDEDPROGRESS, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, reinterpret_cast<DWORD*>(&results.nResult));
+        ExitOnFailure(hr, "Failed to read result from SendEmbeddedProgress results.");
 
         *pnResult = results.nResult;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -340,22 +775,67 @@ public: // IBootstrapperEngine
         __in_z_opt LPCWSTR wzDownloadSource,
         __in DWORD64 qwSize,
         __in BOOTSTRAPPER_UPDATE_HASH_TYPE hashType,
-        __in_z_opt LPCWSTR wzHash
+        __in_z_opt LPCWSTR wzHash,
+        __in_z_opt LPCWSTR wzUpdatePackageId
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETUPDATE_ARGS args = { };
         BAENGINE_SETUPDATE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzLocalSource = wzLocalSource;
         args.wzDownloadSource = wzDownloadSource;
         args.qwSize = qwSize;
         args.hashType = hashType;
         args.wzHash = wzHash;
+        args.wzUpdatePackageId = wzUpdatePackageId;
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetUpdate args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzLocalSource);
+        ExitOnFailure(hr, "Failed to write local source of SetUpdate args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzDownloadSource);
+        ExitOnFailure(hr, "Failed to write download source of SetUpdate args.");
+
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.qwSize);
+        ExitOnFailure(hr, "Failed to write udpate size of SetUpdate args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, static_cast<DWORD>(args.hashType));
+        ExitOnFailure(hr, "Failed to write hash type of SetUpdate args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzHash);
+        ExitOnFailure(hr, "Failed to write hash of SetUpdate args.");
 
-        results.cbSize = sizeof(results);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzHash);
+        ExitOnFailure(hr, "Failed to write hash of SetUpdate args.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETUPDATE, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzUpdatePackageId);
+        ExitOnFailure(hr, "Failed to write update package id to SetUpdate args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetUpdate results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETUPDATE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetUpdate failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetLocalSource(
@@ -364,17 +844,48 @@ public: // IBootstrapperEngine
         __in_z LPCWSTR wzPath
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETLOCALSOURCE_ARGS args = { };
         BAENGINE_SETLOCALSOURCE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzPackageOrContainerId = wzPackageOrContainerId;
         args.wzPayloadId = wzPayloadId;
         args.wzPath = wzPath;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetLocalSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPackageOrContainerId);
+        ExitOnFailure(hr, "Failed to write package or container id of SetLocalSource args.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETLOCALSOURCE, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPayloadId);
+        ExitOnFailure(hr, "Failed to write payload id of SetLocalSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPath);
+        ExitOnFailure(hr, "Failed to write path of SetLocalSource args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetLocalSource results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETLOCALSOURCE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetLocalSource failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetDownloadSource(
@@ -382,22 +893,64 @@ public: // IBootstrapperEngine
         __in_z_opt LPCWSTR wzPayloadId,
         __in_z LPCWSTR wzUrl,
         __in_z_opt LPCWSTR wzUser,
-        __in_z_opt LPCWSTR wzPassword
+        __in_z_opt LPCWSTR wzPassword,
+        __in_z_opt LPCWSTR wzAuthorizationHeader
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETDOWNLOADSOURCE_ARGS args = { };
         BAENGINE_SETDOWNLOADSOURCE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzPackageOrContainerId = wzPackageOrContainerId;
         args.wzPayloadId = wzPayloadId;
         args.wzUrl = wzUrl;
         args.wzUser = wzUser;
         args.wzPassword = wzPassword;
+        args.wzAuthorizationHeader = wzAuthorizationHeader;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETDOWNLOADSOURCE, &args, &results, m_pvBAEngineProcContext);
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPackageOrContainerId);
+        ExitOnFailure(hr, "Failed to write package or container id of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPayloadId);
+        ExitOnFailure(hr, "Failed to write payload id of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzUrl);
+        ExitOnFailure(hr, "Failed to write url of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzUser);
+        ExitOnFailure(hr, "Failed to write user of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPassword);
+        ExitOnFailure(hr, "Failed to write password of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzAuthorizationHeader);
+        ExitOnFailure(hr, "Failed to write authorization header of SetDownloadSource args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetDownloadSource results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETDOWNLOADSOURCE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetDownloadSource failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetVariableNumeric(
@@ -405,16 +958,44 @@ public: // IBootstrapperEngine
         __in LONGLONG llValue
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETVARIABLENUMERIC_ARGS args = { };
         BAENGINE_SETVARIABLENUMERIC_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
         args.llValue = llValue;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableNumeric args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable of SetVariableNumeric args.");
+
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, static_cast<DWORD64>(args.llValue));
+        ExitOnFailure(hr, "Failed to write value of SetVariableNumeric args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableNumeric results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLENUMERIC, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetVariableNumeric failed.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLENUMERIC, &args, &results, m_pvBAEngineProcContext);
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetVariableString(
@@ -423,17 +1004,48 @@ public: // IBootstrapperEngine
         __in BOOL fFormatted
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETVARIABLESTRING_ARGS args = { };
         BAENGINE_SETVARIABLESTRING_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
         args.wzValue = wzValue;
         args.fFormatted = fFormatted;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableString args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable of SetVariableString args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzValue);
+        ExitOnFailure(hr, "Failed to write value of SetVariableString args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.fFormatted);
+        ExitOnFailure(hr, "Failed to write formatted flag of SetVariableString args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableString results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLESTRING, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLESTRING, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetVariableString failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetVariableVersion(
@@ -441,103 +1053,278 @@ public: // IBootstrapperEngine
         __in_z_opt LPCWSTR wzValue
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETVARIABLEVERSION_ARGS args = { };
         BAENGINE_SETVARIABLEVERSION_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
         args.wzValue = wzValue;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableVersion args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable of SetVariableVersion args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzValue);
+        ExitOnFailure(hr, "Failed to write value of SetVariableVersion args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableVersion results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLEVERSION, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLEVERSION, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetVariableVersion failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP CloseSplashScreen()
     {
+        HRESULT hr = S_OK;
         BAENGINE_CLOSESPLASHSCREEN_ARGS args = { };
         BAENGINE_CLOSESPLASHSCREEN_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of CloseSplashScreen args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of CloseSplashScreen results.");
 
-        args.cbSize = sizeof(args);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_CLOSESPLASHSCREEN, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA CloseSplashScreen failed.");
 
-        results.cbSize = sizeof(results);
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_CLOSESPLASHSCREEN, &args, &results, m_pvBAEngineProcContext);
+        return hr;
     }
 
     virtual STDMETHODIMP Detect(
         __in_opt HWND hwndParent
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_DETECT_ARGS args = { };
         BAENGINE_DETECT_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        args.hwndParent = reinterpret_cast<DWORD64>(hwndParent);
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
 
-        args.cbSize = sizeof(args);
-        args.hwndParent = hwndParent;
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Detect args.");
 
-        results.cbSize = sizeof(results);
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.hwndParent);
+        ExitOnFailure(hr, "Failed to write parent window of Detect args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Detect results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_DETECT, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Detect failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_DETECT, &args, &results, m_pvBAEngineProcContext);
+        return hr;
     }
 
     virtual STDMETHODIMP Plan(
         __in BOOTSTRAPPER_ACTION action
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_PLAN_ARGS args = { };
         BAENGINE_PLAN_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.action = action;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Plan args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, static_cast<DWORD>(args.action));
+        ExitOnFailure(hr, "Failed to write parent window of Plan args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Plan results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_PLAN, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_PLAN, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Plan failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP Elevate(
         __in_opt HWND hwndParent
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_ELEVATE_ARGS args = { };
         BAENGINE_ELEVATE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        args.hwndParent = reinterpret_cast<DWORD64>(hwndParent);
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Elevate args.");
 
-        args.cbSize = sizeof(args);
-        args.hwndParent = hwndParent;
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.hwndParent);
+        ExitOnFailure(hr, "Failed to write parent window of Elevate args.");
 
-        results.cbSize = sizeof(results);
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Elevate results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_ELEVATE, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_ELEVATE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Elevate failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP Apply(
         __in HWND hwndParent
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_APPLY_ARGS args = { };
         BAENGINE_APPLY_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        args.hwndParent = reinterpret_cast<DWORD64>(hwndParent);
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Apply args.");
+
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.hwndParent);
+        ExitOnFailure(hr, "Failed to write parent window of Apply args.");
 
-        args.cbSize = sizeof(args);
-        args.hwndParent = hwndParent;
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Apply results.");
 
-        results.cbSize = sizeof(results);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_APPLY, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Apply failed.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_APPLY, &args, &results, m_pvBAEngineProcContext);
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP Quit(
         __in DWORD dwExitCode
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_QUIT_ARGS args = { };
         BAENGINE_QUIT_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.dwExitCode = dwExitCode;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_QUIT, &args, &results, m_pvBAEngineProcContext);
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Quit args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwExitCode);
+        ExitOnFailure(hr, "Failed to write exit code of Quit args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Quit results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_QUIT, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Quit failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP LaunchApprovedExe(
@@ -547,33 +1334,101 @@ public: // IBootstrapperEngine
         __in DWORD dwWaitForInputIdleTimeout
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_LAUNCHAPPROVEDEXE_ARGS args = { };
         BAENGINE_LAUNCHAPPROVEDEXE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        ExitOnNull(wzApprovedExeForElevationId, hr, E_INVALIDARG, "wzApprovedExeForElevationId is required");
 
-        args.cbSize = sizeof(args);
-        args.hwndParent = hwndParent;
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        args.hwndParent = reinterpret_cast<DWORD64>(hwndParent);
         args.wzApprovedExeForElevationId = wzApprovedExeForElevationId;
         args.wzArguments = wzArguments;
         args.dwWaitForInputIdleTimeout = dwWaitForInputIdleTimeout;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_LAUNCHAPPROVEDEXE, &args, &results, m_pvBAEngineProcContext);
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of LaunchApprovedExe args.");
+
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.hwndParent);
+        ExitOnFailure(hr, "Failed to write parent window of LaunchApprovedExe args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzApprovedExeForElevationId);
+        ExitOnFailure(hr, "Failed to write approved exe elevation id of LaunchApprovedExe args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzArguments);
+        ExitOnFailure(hr, "Failed to write arguments of LaunchApprovedExe args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwWaitForInputIdleTimeout);
+        ExitOnFailure(hr, "Failed to write wait for idle input timeout of LaunchApprovedExe args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of LaunchApprovedExe results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_LAUNCHAPPROVEDEXE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA LaunchApprovedExe failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetUpdateSource(
-        __in_z LPCWSTR wzUrl
+        __in_z LPCWSTR wzUrl,
+        __in_z_opt LPCWSTR wzAuthorizationHeader
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETUPDATESOURCE_ARGS args = { };
         BAENGINE_SETUPDATESOURCE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        ExitOnNull(wzUrl, hr, E_INVALIDARG, "wzUrl is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzUrl = wzUrl;
+        args.wzAuthorizationHeader = wzAuthorizationHeader;
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetUpdateSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzUrl);
+        ExitOnFailure(hr, "Failed to write url of SetUpdateSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzAuthorizationHeader);
+        ExitOnFailure(hr, "Failed to write authorization header of SetUpdateSource args.");
 
-        results.cbSize = sizeof(results);
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetUpdateSource results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETUPDATESOURCE, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETUPDATESOURCE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetUpdateSource failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP CompareVersions(
@@ -585,66 +1440,133 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_COMPAREVERSIONS_ARGS args = { };
         BAENGINE_COMPAREVERSIONS_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
         ExitOnNull(pnResult, hr, E_INVALIDARG, "pnResult is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVersion1 = wzVersion1;
         args.wzVersion2 = wzVersion2;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of CompareVersions args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVersion1);
+        ExitOnFailure(hr, "Failed to write first input of CompareVersions args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVersion2);
+        ExitOnFailure(hr, "Failed to write second input of CompareVersions args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of CompareVersions results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_COMPAREVERSIONS, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA CompareVersions failed.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_COMPAREVERSIONS, &args, &results, m_pvBAEngineProcContext);
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from CompareVersions results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, reinterpret_cast<DWORD*>(&results.nResult));
+        ExitOnFailure(hr, "Failed to read result from CompareVersions results.");
 
         *pnResult = results.nResult;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
-public:
-    HRESULT Init()
+private:
+    HRESULT SendRequest(
+        __in DWORD dwMessageType,
+        __in BUFF_BUFFER* pBufferArgs,
+        __in BUFF_BUFFER* pBufferResults,
+        __in PIPE_RPC_RESULT* pRpc
+        )
     {
-        return ::CoCreateFreeThreadedMarshaler(this, &m_pFreeThreadedMarshaler);
+        HRESULT hr = S_OK;
+        BUFF_BUFFER buffer = { };
+
+        hr = CombineArgsAndResults(pBufferArgs, pBufferResults, &buffer);
+        if (SUCCEEDED(hr))
+        {
+            hr = PipeRpcRequest(&m_hRpcPipe, dwMessageType, buffer.pbData, buffer.cbData, pRpc);
+        }
+
+        ReleaseBuffer(buffer);
+        return hr;
     }
 
+    HRESULT CombineArgsAndResults(
+        __in BUFF_BUFFER* pBufferArgs,
+        __in BUFF_BUFFER* pBufferResults,
+        __in BUFF_BUFFER* pBufferCombined
+        )
+    {
+        HRESULT hr = S_OK;
+
+        // Write args to buffer.
+        hr = BuffWriteStreamToBuffer(pBufferCombined, pBufferArgs->pbData, pBufferArgs->cbData);
+        ExitOnFailure(hr, "Failed to write args buffer.");
+
+        // Write results to buffer.
+        hr = BuffWriteStreamToBuffer(pBufferCombined, pBufferResults->pbData, pBufferResults->cbData);
+        ExitOnFailure(hr, "Failed to write results buffer.");
+
+    LExit:
+        return hr;
+    }
+
+public:
     CBalBootstrapperEngine(
-        __in PFN_BOOTSTRAPPER_ENGINE_PROC pfnBAEngineProc,
-        __in_opt LPVOID pvBAEngineProcContext
+        __in HANDLE hPipe,
+        __out HRESULT* phr
         )
     {
         m_cReferences = 1;
-        m_pfnBAEngineProc = pfnBAEngineProc;
-        m_pvBAEngineProcContext = pvBAEngineProcContext;
-        m_pFreeThreadedMarshaler = NULL;
+
+        PipeRpcInitialize(&m_hRpcPipe, hPipe, FALSE);
+
+        *phr = ::CoCreateFreeThreadedMarshaler(this, &m_pFreeThreadedMarshaler);
     }
 
     ~CBalBootstrapperEngine()
     {
+        PipeRpcUninitiailize(&m_hRpcPipe);
         ReleaseObject(m_pFreeThreadedMarshaler);
     }
 
 private:
     long m_cReferences;
-    PFN_BOOTSTRAPPER_ENGINE_PROC m_pfnBAEngineProc;
-    LPVOID m_pvBAEngineProcContext;
+    PIPE_RPC_HANDLE m_hRpcPipe;
     IUnknown* m_pFreeThreadedMarshaler;
 };
 
+
 HRESULT BalBootstrapperEngineCreate(
-    __in PFN_BOOTSTRAPPER_ENGINE_PROC pfnBAEngineProc,
-    __in_opt LPVOID pvBAEngineProcContext,
+    __in HANDLE hPipe,
     __out IBootstrapperEngine** ppBootstrapperEngine
     )
 {
     HRESULT hr = S_OK;
     CBalBootstrapperEngine* pBootstrapperEngine = NULL;
 
-    pBootstrapperEngine = new CBalBootstrapperEngine(pfnBAEngineProc, pvBAEngineProcContext);
+    pBootstrapperEngine = new CBalBootstrapperEngine(hPipe, &hr);
     ExitOnNull(pBootstrapperEngine, hr, E_OUTOFMEMORY, "Failed to allocate new BalBootstrapperEngine object.");
-
-    hr = pBootstrapperEngine->Init();
-    ExitOnFailure(hr, "Failed to initialize CBalBootstrapperEngine.");
+    ExitOnFailure(hr, "Failed to initialize BalBootstrapperEngine.");
 
     hr = pBootstrapperEngine->QueryInterface(IID_PPV_ARGS(ppBootstrapperEngine));
     ExitOnFailure(hr, "Failed to QI for IBootstrapperEngine from BalBootstrapperEngine object.");
diff --git a/src/api/burn/balutil/inc/BalBootstrapperEngine.h b/src/api/burn/balutil/BalBootstrapperEngine.h
index 45131d98..b3bd4ca7 100644
--- a/src/api/burn/balutil/inc/BalBootstrapperEngine.h
+++ b/src/api/burn/balutil/BalBootstrapperEngine.h
@@ -1,17 +1,7 @@
+#pragma once
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-// function declarations
-
 HRESULT BalBootstrapperEngineCreate(
-    __in PFN_BOOTSTRAPPER_ENGINE_PROC pfnBAEngineProc,
-    __in_opt LPVOID pvBAEngineProcContext,
+    __in HANDLE hEnginePipe,
     __out IBootstrapperEngine** ppEngineForApplication
     );
-
-#ifdef __cplusplus
-}
-#endif
diff --git a/src/api/burn/balutil/balinfo.cpp b/src/api/burn/balutil/balinfo.cpp
index 751ba4f1..6f609a40 100644
--- a/src/api/burn/balutil/balinfo.cpp
+++ b/src/api/burn/balutil/balinfo.cpp
@@ -223,7 +223,6 @@ LExit:
 DAPI_(HRESULT) BalInfoAddUpdateBundleAsPackage(
     __in BAL_INFO_PACKAGES* pPackages,
     __in_z LPCWSTR wzId,
-    __in_z LPCWSTR /*wzPreviousId*/,
     __out_opt BAL_INFO_PACKAGE** ppPackage
     )
 {
@@ -356,7 +355,7 @@ DAPI_(HRESULT) BalSetOverridableVariablesFromEngine(
         LPCWSTR wzVariableValue = pCommand->rgVariableValues[i];
 
         hr = DictGetValue(pOverridableVariables->sdVariables, wzVariableName, reinterpret_cast<void**>(&pOverridableVariable));
-        if (E_NOTFOUND == hr)
+        if (E_NOTFOUND == hr || E_INVALIDARG == hr)
         {
             BalLog(BOOTSTRAPPER_LOG_LEVEL_ERROR, "Ignoring attempt to set non-overridable variable: '%ls'.", wzVariableName);
             hr = S_OK;
@@ -549,16 +548,16 @@ static HRESULT ParseBalPackageInfoFromXml(
     }
     ExitOnFailure(hr, "Failed to parse all WixBalPackageInfo elements.");
 
-    hr = XmlSelectNodes(pixdManifest, L"/BootstrapperApplicationData/WixMbaPrereqInformation", &pNodeList);
+    hr = XmlSelectNodes(pixdManifest, L"/BootstrapperApplicationData/WixPrereqInformation", &pNodeList);
     ExitOnFailure(hr, "Failed to select all packages.");
 
     while (S_OK == (hr = XmlNextElement(pNodeList, &pNode, NULL)))
     {
         hr = XmlGetAttributeEx(pNode, L"PackageId", &scz);
-        ExitOnRequiredXmlQueryFailure(hr, "Failed to get package identifier for WixMbaPrereqInformation.");
+        ExitOnRequiredXmlQueryFailure(hr, "Failed to get package identifier for WixPrereqInformation.");
 
         hr = BalInfoFindPackageById(pPackages, scz, &pPackage);
-        ExitOnFailure(hr, "Failed to find package specified in WixMbaPrereqInformation: %ls", scz);
+        ExitOnFailure(hr, "Failed to find package specified in WixPrereqInformation: %ls", scz);
 
         pPackage->fPrereqPackage = TRUE;
 
@@ -570,7 +569,7 @@ static HRESULT ParseBalPackageInfoFromXml(
 
         ReleaseNullObject(pNode);
     }
-    ExitOnFailure(hr, "Failed to parse all WixMbaPrereqInformation elements.");
+    ExitOnFailure(hr, "Failed to parse all WixPrereqInformation elements.");
 
     if (S_FALSE == hr)
     {
diff --git a/src/api/burn/balutil/balutil.cpp b/src/api/burn/balutil/balutil.cpp
index 2d80878c..a77ff7d0 100644
--- a/src/api/burn/balutil/balutil.cpp
+++ b/src/api/burn/balutil/balutil.cpp
@@ -3,8 +3,39 @@
 #include "precomp.h"
 
 const DWORD VARIABLE_GROW_FACTOR = 80;
+static DWORD vdwDebuggerCheck = 0;
 static IBootstrapperEngine* vpEngine = NULL;
 
+static HRESULT ParseCommandLine(
+    __inout_z LPWSTR *psczPipeBaseName,
+    __inout_z LPWSTR *psczPipeSecret,
+    __out DWORD64 *pqwEngineAPIVersion
+    );
+static HRESULT ConnectToEngine(
+    __in_z LPCWSTR wzPipeBaseName,
+    __in_z LPCWSTR wzPipeSecret,
+    __out HANDLE *phBAPipe,
+    __out HANDLE *phEnginePipe
+    );
+static HRESULT ConnectAndVerify(
+    __in_z LPCWSTR wzPipeName,
+    __in_z LPCWSTR wzPipeSecret,
+    __in DWORD cbPipeSecret,
+    __out HANDLE *phPipe
+    );
+static HRESULT PumpMessages(
+    __in HANDLE hPipe,
+    __in IBootstrapperApplication* pApplication,
+    __in IBootstrapperEngine* pEngine
+    );
+static void MsgProc(
+    __in BOOTSTRAPPER_APPLICATION_MESSAGE messageType,
+    __in_bcount(cbData) LPVOID pvData,
+    __in DWORD cbData,
+    __in IBootstrapperApplication* pApplication,
+    __in IBootstrapperEngine* pEngine
+    );
+
 // prototypes
 
 DAPI_(void) BalInitialize(
@@ -17,38 +48,136 @@ DAPI_(void) BalInitialize(
     vpEngine = pEngine;
 }
 
-DAPI_(HRESULT) BalInitializeFromCreateArgs(
-    __in const BOOTSTRAPPER_CREATE_ARGS* pArgs,
-    __out_opt IBootstrapperEngine** ppEngine
+DAPI_(void) BalUninitialize()
+{
+    ReleaseNullObject(vpEngine);
+}
+
+DAPI_(HRESULT) BootstrapperApplicationRun(
+    __in IBootstrapperApplication* pApplication
     )
 {
     HRESULT hr = S_OK;
+    BOOL fComInitialized = FALSE;
+    DWORD64 qwEngineAPIVersion = 0;
+    LPWSTR sczPipeBaseName = NULL;
+    LPWSTR sczPipeSecret = NULL;
+    HANDLE hBAPipe = INVALID_HANDLE_VALUE;
+    HANDLE hEnginePipe = INVALID_HANDLE_VALUE;
     IBootstrapperEngine* pEngine = NULL;
+    BOOL fInitializedBal = FALSE;
+
+    // initialize COM
+    hr = ::CoInitializeEx(NULL, COINIT_MULTITHREADED);
+    ExitOnFailure(hr, "Failed to initialize COM.");
+    fComInitialized = TRUE;
+
+    hr = ParseCommandLine(&sczPipeBaseName, &sczPipeSecret, &qwEngineAPIVersion);
+    BalExitOnFailure(hr, "Failed to parse command line.");
 
-    hr = BalBootstrapperEngineCreate(pArgs->pfnBootstrapperEngineProc, pArgs->pvBootstrapperEngineProcContext, &pEngine);
-    ExitOnFailure(hr, "Failed to create BalBootstrapperEngine.");
+    // TODO: Validate the engine API version.
+
+    hr = ConnectToEngine(sczPipeBaseName, sczPipeSecret, &hBAPipe, &hEnginePipe);
+    BalExitOnFailure(hr, "Failed to connect to engine.");
+
+    hr = BalBootstrapperEngineCreate(hEnginePipe, &pEngine);
+    BalExitOnFailure(hr, "Failed to create bootstrapper engine.");
 
     BalInitialize(pEngine);
+    fInitializedBal = TRUE;
+
+    BootstrapperApplicationDebuggerCheck();
 
-    if (ppEngine)
+    hr = MsgPump(hBAPipe, pApplication, pEngine);
+    BalExitOnFailure(hr, "Failed while pumping messages.");
+
+LExit:
+    if (fInitializedBal)
     {
-        *ppEngine = pEngine;
+        BalUninitialize();
     }
-    pEngine = NULL;
 
-LExit:
-    ReleaseObject(pEngine);
+    ReleaseNullObject(pEngine);
+    ReleasePipeHandle(hEnginePipe);
+    ReleasePipeHandle(hBAPipe);
+    ReleaseStr(sczPipeSecret);
+    ReleaseStr(sczPipeBaseName);
+
+    if (fComInitialized)
+    {
+        ::CoUninitialize();
+    }
 
     return hr;
 }
 
-
-DAPI_(void) BalUninitialize()
+DAPI_(VOID) BootstrapperApplicationDebuggerCheck()
 {
-    ReleaseNullObject(vpEngine);
+    HRESULT hr = S_OK;
+    HKEY hk = NULL;
+    BOOL fDebug = FALSE;
+    LPWSTR sczDebugBootstrapperApplications = NULL;
+    LPWSTR sczDebugBootstrapperApplication = NULL;
+    LPWSTR sczModulePath = NULL;
+    LPCWSTR wzModuleFilename = NULL;
+    WCHAR wzMessage[1024] = { };
+
+    if (0 == vdwDebuggerCheck)
+    {
+        ++vdwDebuggerCheck;
+
+        hr = RegOpen(HKEY_LOCAL_MACHINE, L"System\\CurrentControlSet\\Control\\Session Manager\\Environment", KEY_QUERY_VALUE, &hk);
+        if (SUCCEEDED(hr))
+        {
+            hr = RegReadString(hk, L"WixDebugBootstrapperApplications", &sczDebugBootstrapperApplications);
+            if (SUCCEEDED(hr) && sczDebugBootstrapperApplications && *sczDebugBootstrapperApplications &&
+                sczDebugBootstrapperApplications[0] != L'0' && !sczDebugBootstrapperApplications[1])
+            {
+                hr = PathForCurrentProcess(&sczModulePath, NULL);
+                if (SUCCEEDED(hr) && sczModulePath && *sczModulePath)
+                {
+                    wzModuleFilename = PathFile(sczModulePath);
+                    if (wzModuleFilename)
+                    {
+                        fDebug = TRUE;
+                    }
+                }
+            }
+            else
+            {
+                hr = RegReadString(hk, L"WixDebugBootstrapperApplication", &sczDebugBootstrapperApplication);
+                if (SUCCEEDED(hr) && sczDebugBootstrapperApplication && *sczDebugBootstrapperApplication)
+                {
+                    hr = PathForCurrentProcess(&sczModulePath, NULL);
+                    if (SUCCEEDED(hr) && sczModulePath && *sczModulePath)
+                    {
+                        wzModuleFilename = PathFile(sczModulePath);
+                        if (wzModuleFilename && CSTR_EQUAL == ::CompareStringOrdinal(sczDebugBootstrapperApplication, -1, wzModuleFilename, -1, TRUE))
+                        {
+                            fDebug = TRUE;
+                        }
+                    }
+                }
+            }
+
+            if (fDebug)
+            {
+                hr = ::StringCchPrintfW(wzMessage, countof(wzMessage), L"To debug the boostrapper application process %ls\n\nSet breakpoints and attach a debugger to process id: %d (0x%x)", wzModuleFilename, ::GetCurrentProcessId(), ::GetCurrentProcessId());
+
+                if (SUCCEEDED(hr))
+                {
+                    ::MessageBoxW(NULL, wzMessage, L"WiX Bootstrapper Application", MB_SERVICE_NOTIFICATION | MB_TOPMOST | MB_ICONQUESTION | MB_OK | MB_SYSTEMMODAL);
+                }
+            }
+        }
+    }
+
+    ReleaseRegKey(hk);
+    ReleaseStr(sczModulePath);
+    ReleaseStr(sczDebugBootstrapperApplication);
+    ReleaseStr(sczDebugBootstrapperApplications);
 }
 
-
 DAPI_(HRESULT) BalManifestLoad(
     __in HMODULE hBootstrapperApplicationModule,
     __out IXMLDOMDocument** ppixdManifest
@@ -671,3 +800,146 @@ LExit:
 
     return hr;
 }
+
+
+static HRESULT ParseCommandLine(
+    __inout_z LPWSTR *psczPipeBaseName,
+    __inout_z LPWSTR *psczPipeSecret,
+    __out DWORD64 *pqwEngineAPIVersion
+    )
+{
+    HRESULT hr = S_OK;
+    LPWSTR wzCommandLine = ::GetCommandLineW();
+    int argc = 0;
+    LPWSTR* argv = NULL;
+
+    *pqwEngineAPIVersion = 0;
+
+    hr = AppParseCommandLine(wzCommandLine, &argc, &argv);
+    ExitOnFailure(hr, "Failed to parse command line.");
+
+    // Skip the executable full path in argv[0].
+    for (int i = 1; i < argc; ++i)
+    {
+        if (argv[i][0] == L'-')
+        {
+            if (CSTR_EQUAL == ::CompareStringOrdinal(&argv[i][1], -1, BOOTSTRAPPER_APPLICATION_COMMANDLINE_SWITCH_API_VERSION, -1, TRUE))
+            {
+                if (i + 1 >= argc)
+                {
+                    BalExitOnRootFailure(hr = E_INVALIDARG, "Must specify an api version.");
+                }
+
+                ++i;
+
+                hr = StrStringToUInt64(argv[i], 0, pqwEngineAPIVersion);
+                BalExitOnFailure(hr, "Failed to parse api version: %ls", argv[i]);
+            }
+            else if (CSTR_EQUAL == ::CompareStringOrdinal(&argv[i][1], -1, BOOTSTRAPPER_APPLICATION_COMMANDLINE_SWITCH_PIPE_NAME, -1, TRUE))
+            {
+                if (i + 2 >= argc)
+                {
+                    BalExitOnRootFailure(hr = E_INVALIDARG, "Must specify a pipe name and pipe secret.");
+                }
+
+                ++i;
+
+                hr = StrAllocString(psczPipeBaseName, argv[i], 0);
+                BalExitOnFailure(hr, "Failed to copy pipe name.");
+
+                ++i;
+
+                hr = StrAllocString(psczPipeSecret, argv[i], 0);
+                BalExitOnFailure(hr, "Failed to copy pipe secret.");
+            }
+        }
+        else
+        {
+            BalExitWithRootFailure(hr, E_INVALIDARG, "Invalid argument: %ls", argv[i]);
+        }
+    }
+
+LExit:
+    if (argv)
+    {
+        AppFreeCommandLineArgs(argv);
+    }
+
+    return hr;
+}
+
+static HRESULT ConnectToEngine(
+    __in_z LPCWSTR wzPipeBaseName,
+    __in_z LPCWSTR wzPipeSecret,
+    __out HANDLE *phBAPipe,
+    __out HANDLE *phEnginePipe
+    )
+{
+    HRESULT hr = S_OK;
+    LPWSTR sczBAPipeName = NULL;
+    LPWSTR sczEnginePipeName = NULL;
+    HANDLE hBAPipe = INVALID_HANDLE_VALUE;
+    HANDLE hEnginePipe = INVALID_HANDLE_VALUE;
+
+    DWORD cbPipeSecret = lstrlenW(wzPipeSecret) * sizeof(WCHAR);
+
+    hr = StrAllocFormatted(&sczBAPipeName, L"%ls%ls", wzPipeBaseName, L".BA");
+    ExitOnFailure(hr, "Failed to allocate BA pipe name.");
+
+    hr = StrAllocFormatted(&sczEnginePipeName, L"%ls%ls", wzPipeBaseName, L".BAEngine");
+    ExitOnFailure(hr, "Failed to allocate BA engine pipe name.");
+
+    hr = ConnectAndVerify(sczBAPipeName, wzPipeSecret, cbPipeSecret, &hBAPipe);
+    BalExitOnFailure(hr, "Failed to connect to bootstrapper application pipe.");
+
+    hr = ConnectAndVerify(sczEnginePipeName, wzPipeSecret, cbPipeSecret, &hEnginePipe);
+    BalExitOnFailure(hr, "Failed to connect to engine pipe.");
+
+    *phBAPipe = hBAPipe;
+    hBAPipe = INVALID_HANDLE_VALUE;
+
+    *phEnginePipe = hEnginePipe;
+    hEnginePipe = INVALID_HANDLE_VALUE;
+
+LExit:
+    ReleasePipeHandle(hEnginePipe);
+    ReleasePipeHandle(hBAPipe);
+    ReleaseStr(sczEnginePipeName);
+    ReleaseStr(sczBAPipeName);
+
+    return hr;
+}
+
+static HRESULT ConnectAndVerify(
+    __in_z LPCWSTR wzPipeName,
+    __in_z LPCWSTR wzPipeSecret,
+    __in DWORD cbPipeSecret,
+    __out HANDLE *phPipe
+    )
+{
+    HRESULT hr = S_OK;
+    HRESULT hrConnect = S_OK;
+    HANDLE hPipe = INVALID_HANDLE_VALUE;
+
+    hr = PipeClientConnect(wzPipeName, &hPipe);
+    BalExitOnFailure(hr, "Failed to connect to pipe.");
+
+    hr = FileWriteHandle(hPipe, reinterpret_cast<LPCBYTE>(&cbPipeSecret), sizeof(cbPipeSecret));
+    BalExitOnFailure(hr, "Failed to write secret size to pipe.");
+
+    hr = FileWriteHandle(hPipe, reinterpret_cast<LPCBYTE>(wzPipeSecret), cbPipeSecret);
+    BalExitOnFailure(hr, "Failed to write secret size to pipe.");
+
+    FileReadHandle(hPipe, reinterpret_cast<LPBYTE>(&hrConnect), sizeof(hrConnect));
+    BalExitOnFailure(hr, "Failed to read connect result from pipe.");
+
+    BalExitOnFailure(hrConnect, "Failed connect result from pipe.");
+
+    *phPipe = hPipe;
+    hPipe = INVALID_HANDLE_VALUE;
+
+LExit:
+    ReleasePipeHandle(hPipe);
+
+    return hr;
+}
diff --git a/src/api/burn/balutil/balutil.vcxproj b/src/api/burn/balutil/balutil.vcxproj
index d5cd146b..8f93d636 100644
--- a/src/api/burn/balutil/balutil.vcxproj
+++ b/src/api/burn/balutil/balutil.vcxproj
@@ -53,6 +53,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <ClCompile Include="BalBaseBAFunctionsProc.cpp" />
     <ClCompile Include="BalBootstrapperEngine.cpp" />
     <ClCompile Include="balcondition.cpp" />
     <ClCompile Include="balinfo.cpp" />
@@ -61,23 +62,23 @@
     <ClCompile Include="precomp.cpp">
       <PrecompiledHeader>Create</PrecompiledHeader>
     </ClCompile>
+    <ClCompile Include="msg.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="inc\BAFunctions.h" />
     <ClInclude Include="inc\BalBaseBAFunctions.h" />
     <ClInclude Include="inc\BalBaseBAFunctionsProc.h" />
     <ClInclude Include="inc\BalBaseBootstrapperApplication.h" />
-    <ClInclude Include="inc\BalBaseBootstrapperApplicationProc.h" />
-    <ClInclude Include="inc\BalBootstrapperEngine.h" />
     <ClInclude Include="inc\balcondition.h" />
     <ClInclude Include="inc\balinfo.h" />
     <ClInclude Include="inc\balretry.h" />
     <ClInclude Include="inc\balutil.h" />
     <ClInclude Include="inc\IBAFunctions.h" />
     <ClInclude Include="inc\IBootstrapperApplication.h" />
-    <ClInclude Include="inc\IBootstrapperApplicationFactory.h" />
     <ClInclude Include="inc\IBootstrapperEngine.h" />
+    <ClInclude Include="BalBootstrapperEngine.h" />
     <ClInclude Include="precomp.h" />
+    <ClInclude Include="msg.h" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/api/burn/balutil/inc/BAFunctions.h b/src/api/burn/balutil/inc/BAFunctions.h
index 4a0b8599..7908a74c 100644
--- a/src/api/burn/balutil/inc/BAFunctions.h
+++ b/src/api/burn/balutil/inc/BAFunctions.h
@@ -1,6 +1,7 @@
 #pragma once
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
+#include "IBootstrapperEngine.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -9,12 +10,14 @@ extern "C" {
 // The first 1024 messages are reserved so that the BA messages have the same value here.
 enum BA_FUNCTIONS_MESSAGE
 {
+    BA_FUNCTIONS_MESSAGE_ONCREATE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONCREATE,
+    BA_FUNCTIONS_MESSAGE_ONDESTROY = BOOTSTRAPPER_APPLICATION_MESSAGE_ONDESTROY,
+    BA_FUNCTIONS_MESSAGE_ONSTARTUP = BOOTSTRAPPER_APPLICATION_MESSAGE_ONSTARTUP,
+    BA_FUNCTIONS_MESSAGE_ONSHUTDOWN = BOOTSTRAPPER_APPLICATION_MESSAGE_ONSHUTDOWN,
     BA_FUNCTIONS_MESSAGE_ONDETECTBEGIN = BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTBEGIN,
     BA_FUNCTIONS_MESSAGE_ONDETECTCOMPLETE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPLETE,
     BA_FUNCTIONS_MESSAGE_ONPLANBEGIN = BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANBEGIN,
     BA_FUNCTIONS_MESSAGE_ONPLANCOMPLETE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPLETE,
-    BA_FUNCTIONS_MESSAGE_ONSTARTUP = BOOTSTRAPPER_APPLICATION_MESSAGE_ONSTARTUP,
-    BA_FUNCTIONS_MESSAGE_ONSHUTDOWN = BOOTSTRAPPER_APPLICATION_MESSAGE_ONSHUTDOWN,
     BA_FUNCTIONS_MESSAGE_ONDETECTFORWARDCOMPATIBLEBUNDLE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTFORWARDCOMPATIBLEBUNDLE,
     BA_FUNCTIONS_MESSAGE_ONDETECTUPDATEBEGIN = BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATEBEGIN,
     BA_FUNCTIONS_MESSAGE_ONDETECTUPDATE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATE,
@@ -81,8 +84,6 @@ enum BA_FUNCTIONS_MESSAGE
     BA_FUNCTIONS_MESSAGE_ONCACHEPAYLOADEXTRACTCOMPLETE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTCOMPLETE,
     BA_FUNCTIONS_MESSAGE_ONCACHEPAYLOADEXTRACTPROGRESS = BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTPROGRESS,
     BA_FUNCTIONS_MESSAGE_ONPLANROLLBACKBOUNDARY = BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANROLLBACKBOUNDARY,
-    BA_FUNCTIONS_MESSAGE_ONSETUPDATEBEGIN = BOOTSTRAPPER_APPLICATION_MESSAGE_ONSETUPDATEBEGIN,
-    BA_FUNCTIONS_MESSAGE_ONSETUPDATECOMPLETE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONSETUPDATECOMPLETE,
     BA_FUNCTIONS_MESSAGE_ONDETECTCOMPATIBLEMSIPACKAGE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPATIBLEMSIPACKAGE,
     BA_FUNCTIONS_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGEBEGIN = BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGEBEGIN,
     BA_FUNCTIONS_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE,
@@ -117,7 +118,8 @@ struct BA_FUNCTIONS_CREATE_ARGS
 {
     DWORD cbSize;
     DWORD64 qwBAFunctionsAPIVersion;
-    BOOTSTRAPPER_CREATE_ARGS* pBootstrapperCreateArgs;
+    IBootstrapperEngine* pEngine;
+    BOOTSTRAPPER_COMMAND* pCommand;
 };
 
 struct BA_FUNCTIONS_CREATE_RESULTS
diff --git a/src/api/burn/balutil/inc/BalBaseBAFunctions.h b/src/api/burn/balutil/inc/BalBaseBAFunctions.h
index 6ad109c3..33b71324 100644
--- a/src/api/burn/balutil/inc/BalBaseBAFunctions.h
+++ b/src/api/burn/balutil/inc/BalBaseBAFunctions.h
@@ -1,16 +1,12 @@
 #pragma once
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
-
 #include <windows.h>
 #include <msiquery.h>
 
-#include "BAFunctions.h"
+#include <batypes.h>
+
 #include "IBAFunctions.h"
-#include "BootstrapperEngine.h"
-#include "BootstrapperApplication.h"
-#include "IBootstrapperEngine.h"
-#include "IBootstrapperApplication.h"
 
 class CBalBaseBAFunctions : public IBAFunctions
 {
@@ -69,8 +65,7 @@ public: // IBootstrapperApplication
     virtual STDMETHODIMP_(HRESULT) BAProc(
         __in BOOTSTRAPPER_APPLICATION_MESSAGE /*message*/,
         __in const LPVOID /*pvArgs*/,
-        __inout LPVOID /*pvResults*/,
-        __in_opt LPVOID /*pvContext*/
+        __inout LPVOID /*pvResults*/
         )
     {
         return E_NOTIMPL;
@@ -80,12 +75,31 @@ public: // IBootstrapperApplication
         __in BOOTSTRAPPER_APPLICATION_MESSAGE /*message*/,
         __in const LPVOID /*pvArgs*/,
         __inout LPVOID /*pvResults*/,
-        __inout HRESULT* /*phr*/,
-        __in_opt LPVOID /*pvContext*/
+        __inout HRESULT* /*phr*/
         )
     {
     }
 
+    virtual STDMETHODIMP OnCreate(
+        __in IBootstrapperEngine* pEngine,
+        __in BOOTSTRAPPER_COMMAND* /*pCommand*/
+        )
+    {
+        HRESULT hr = S_OK;
+
+        pEngine->AddRef();
+        m_pEngine = pEngine;
+
+        return hr;
+    }
+
+    virtual STDMETHODIMP OnDestroy(
+        __in BOOL /*fReload*/
+    )
+    {
+        return S_OK;
+    }
+
     virtual STDMETHODIMP OnStartup()
     {
         return S_OK;
@@ -837,20 +851,6 @@ public: // IBootstrapperApplication
         return S_OK;
     }
 
-    virtual STDMETHODIMP OnSetUpdateBegin()
-    {
-        return S_OK;
-    }
-
-    virtual STDMETHODIMP OnSetUpdateComplete(
-        __in HRESULT /*hrStatus*/,
-        __in_z_opt LPCWSTR /*wzPreviousPackageId*/,
-        __in_z_opt LPCWSTR /*wzNewPackageId*/
-        )
-    {
-        return S_OK;
-    }
-
     virtual STDMETHODIMP OnPlanRestoreRelatedBundle(
         __in_z LPCWSTR /*wzBundleId*/,
         __in BOOTSTRAPPER_REQUEST_STATE /*recommendedState*/,
@@ -996,22 +996,13 @@ public: // IBAFunctions
     }
 
 protected:
-    CBalBaseBAFunctions(
-        __in HMODULE hModule,
-        __in IBootstrapperEngine* pEngine,
-        __in const BA_FUNCTIONS_CREATE_ARGS* pArgs
-        )
+    CBalBaseBAFunctions(HMODULE hModule)
     {
         m_cReferences = 1;
         m_hModule = hModule;
-        pEngine->AddRef();
-        m_pEngine = pEngine;
 
-        memcpy_s(&m_command, sizeof(m_command), pArgs->pBootstrapperCreateArgs->pCommand, sizeof(BOOTSTRAPPER_COMMAND));
-        memcpy_s(&m_baCreateArgs, sizeof(m_baCreateArgs), pArgs->pBootstrapperCreateArgs, sizeof(BOOTSTRAPPER_CREATE_ARGS));
-        memcpy_s(&m_bafCreateArgs, sizeof(m_bafCreateArgs), pArgs, sizeof(BA_FUNCTIONS_CREATE_ARGS));
-        m_baCreateArgs.pCommand = &m_command;
-        m_bafCreateArgs.pBootstrapperCreateArgs = &m_baCreateArgs;
+        m_hwndParent = NULL;
+        m_pEngine = NULL;
     }
 
     virtual ~CBalBaseBAFunctions()
@@ -1025,8 +1016,5 @@ private:
 protected:
     IBootstrapperEngine* m_pEngine;
     HMODULE m_hModule;
-    BA_FUNCTIONS_CREATE_ARGS m_bafCreateArgs;
-    BOOTSTRAPPER_CREATE_ARGS m_baCreateArgs;
-    BOOTSTRAPPER_COMMAND m_command;
     HWND m_hwndParent;
 };
diff --git a/src/api/burn/balutil/inc/BalBaseBAFunctionsProc.h b/src/api/burn/balutil/inc/BalBaseBAFunctionsProc.h
index 728bd2b5..65eeb0b4 100644
--- a/src/api/burn/balutil/inc/BalBaseBAFunctionsProc.h
+++ b/src/api/burn/balutil/inc/BalBaseBAFunctionsProc.h
@@ -1,191 +1,15 @@
 #pragma once
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
-
-#include "BalBaseBootstrapperApplicationProc.h"
-#include "BAFunctions.h"
-#include "IBAFunctions.h"
-
-static HRESULT BalBaseBAFunctionsProcOnThemeLoaded(
-    __in IBAFunctions* pBAFunctions,
-    __in BA_FUNCTIONS_ONTHEMELOADED_ARGS* pArgs,
-    __inout BA_FUNCTIONS_ONTHEMELOADED_RESULTS* /*pResults*/
-    )
-{
-    return pBAFunctions->OnThemeLoaded(pArgs->hWnd);
-}
-
-static HRESULT BalBaseBAFunctionsProcWndProc(
-    __in IBAFunctions* pBAFunctions,
-    __in BA_FUNCTIONS_WNDPROC_ARGS* pArgs,
-    __inout BA_FUNCTIONS_WNDPROC_RESULTS* pResults
-    )
-{
-    return pBAFunctions->WndProc(pArgs->hWnd, pArgs->uMsg, pArgs->wParam, pArgs->lParam, &pResults->fProcessed, &pResults->lResult);
-}
-
-static HRESULT BalBaseBAFunctionsProcOnThemeControlLoading(
-    __in IBAFunctions* pBAFunctions,
-    __in BA_FUNCTIONS_ONTHEMECONTROLLOADING_ARGS* pArgs,
-    __inout BA_FUNCTIONS_ONTHEMECONTROLLOADING_RESULTS* pResults
-    )
-{
-    return pBAFunctions->OnThemeControlLoading(pArgs->wzName, &pResults->fProcessed, &pResults->wId, &pResults->dwAutomaticBehaviorType);
-}
-
-static HRESULT BalBaseBAFunctionsProcOnThemeControlWmCommand(
-    __in IBAFunctions* pBAFunctions,
-    __in BA_FUNCTIONS_ONTHEMECONTROLWMCOMMAND_ARGS* pArgs,
-    __inout BA_FUNCTIONS_ONTHEMECONTROLWMCOMMAND_RESULTS* pResults
-    )
-{
-    return pBAFunctions->OnThemeControlWmCommand(pArgs->wParam, pArgs->wzName, pArgs->wId, pArgs->hWnd, &pResults->fProcessed, &pResults->lResult);
-}
-
-static HRESULT BalBaseBAFunctionsProcOnThemeControlWmNotify(
-    __in IBAFunctions* pBAFunctions,
-    __in BA_FUNCTIONS_ONTHEMECONTROLWMNOTIFY_ARGS* pArgs,
-    __inout BA_FUNCTIONS_ONTHEMECONTROLWMNOTIFY_RESULTS* pResults
-    )
-{
-    return pBAFunctions->OnThemeControlWmNotify(pArgs->lParam, pArgs->wzName, pArgs->wId, pArgs->hWnd, &pResults->fProcessed, &pResults->lResult);
-}
-
-static HRESULT BalBaseBAFunctionsProcOnThemeControlLoaded(
-    __in IBAFunctions* pBAFunctions,
-    __in BA_FUNCTIONS_ONTHEMECONTROLLOADED_ARGS* pArgs,
-    __inout BA_FUNCTIONS_ONTHEMECONTROLLOADED_RESULTS* pResults
-    )
-{
-    return pBAFunctions->OnThemeControlLoaded(pArgs->wzName, pArgs->wId, pArgs->hWnd, &pResults->fProcessed);
-}
-
 /*******************************************************************
 BalBaseBAFunctionsProc - requires pvContext to be of type IBAFunctions.
 Provides a default mapping between the message based BAFunctions interface and
 the COM-based BAFunctions interface.
 
 *******************************************************************/
-static HRESULT WINAPI BalBaseBAFunctionsProc(
+HRESULT WINAPI BalBaseBAFunctionsProc(
     __in BA_FUNCTIONS_MESSAGE message,
     __in const LPVOID pvArgs,
     __inout LPVOID pvResults,
     __in_opt LPVOID pvContext
-    )
-{
-    IBAFunctions* pBAFunctions = reinterpret_cast<IBAFunctions*>(pvContext);
-    HRESULT hr = pBAFunctions->BAFunctionsProc(message, pvArgs, pvResults, pvContext);
-
-    if (E_NOTIMPL == hr)
-    {
-        switch (message)
-        {
-        case BA_FUNCTIONS_MESSAGE_ONDETECTBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONPLANCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONSTARTUP:
-        case BA_FUNCTIONS_MESSAGE_ONSHUTDOWN:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTFORWARDCOMPATIBLEBUNDLE:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTUPDATEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTUPDATE:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTUPDATECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTRELATEDBUNDLE:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTPACKAGEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTRELATEDMSIPACKAGE:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTPATCHTARGET:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTMSIFEATURE:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTPACKAGECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANRELATEDBUNDLE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANPACKAGEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONPLANPATCHTARGET:
-        case BA_FUNCTIONS_MESSAGE_ONPLANMSIFEATURE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANPACKAGECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONAPPLYBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONELEVATEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONELEVATECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONPROGRESS:
-        case BA_FUNCTIONS_MESSAGE_ONERROR:
-        case BA_FUNCTIONS_MESSAGE_ONREGISTERBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONREGISTERCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEPACKAGEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEACQUIREBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEACQUIREPROGRESS:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEACQUIRERESOLVING:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEACQUIRECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEVERIFYBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEVERIFYCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEPACKAGECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONCACHECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONEXECUTEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPACKAGEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPATCHTARGET:
-        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPROGRESS:
-        case BA_FUNCTIONS_MESSAGE_ONEXECUTEMSIMESSAGE:
-        case BA_FUNCTIONS_MESSAGE_ONEXECUTEFILESINUSE:
-        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPACKAGECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONEXECUTECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONUNREGISTERBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONUNREGISTERCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONAPPLYCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONLAUNCHAPPROVEDEXEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONLAUNCHAPPROVEDEXECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANMSIPACKAGE:
-        case BA_FUNCTIONS_MESSAGE_ONBEGINMSITRANSACTIONBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONBEGINMSITRANSACTIONCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONCOMMITMSITRANSACTIONBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONCOMMITMSITRANSACTIONCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONROLLBACKMSITRANSACTIONBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONROLLBACKMSITRANSACTIONCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONPAUSEAUTOMATICUPDATESBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONPAUSEAUTOMATICUPDATESCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONSYSTEMRESTOREPOINTBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONSYSTEMRESTOREPOINTCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANNEDPACKAGE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANFORWARDCOMPATIBLEBUNDLE:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEVERIFYPROGRESS:
-        case BA_FUNCTIONS_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEPAYLOADEXTRACTBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEPAYLOADEXTRACTCOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEPAYLOADEXTRACTPROGRESS:
-        case BA_FUNCTIONS_MESSAGE_ONPLANROLLBACKBOUNDARY:
-        case BA_FUNCTIONS_MESSAGE_ONSETUPDATEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONSETUPDATECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTCOMPATIBLEMSIPACKAGE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGEBEGIN:
-        case BA_FUNCTIONS_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANRESTORERELATEDBUNDLE:
-        case BA_FUNCTIONS_MESSAGE_ONPLANRELATEDBUNDLETYPE:
-        case BA_FUNCTIONS_MESSAGE_ONAPPLYDOWNGRADE:
-        case BA_FUNCTIONS_MESSAGE_ONEXECUTEPROCESSCANCEL:
-        case BA_FUNCTIONS_MESSAGE_ONDETECTRELATEDBUNDLEPACKAGE:
-        case BA_FUNCTIONS_MESSAGE_ONCACHEPACKAGENONVITALVALIDATIONFAILURE:
-            hr = BalBaseBootstrapperApplicationProc((BOOTSTRAPPER_APPLICATION_MESSAGE)message, pvArgs, pvResults, pvContext);
-            break;
-        case BA_FUNCTIONS_MESSAGE_ONTHEMELOADED:
-            hr = BalBaseBAFunctionsProcOnThemeLoaded(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMELOADED_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMELOADED_RESULTS*>(pvResults));
-            break;
-        case BA_FUNCTIONS_MESSAGE_WNDPROC:
-            hr = BalBaseBAFunctionsProcWndProc(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_WNDPROC_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_WNDPROC_RESULTS*>(pvResults));
-            break;
-        case BA_FUNCTIONS_MESSAGE_ONTHEMECONTROLLOADING:
-            hr = BalBaseBAFunctionsProcOnThemeControlLoading(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLLOADING_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLLOADING_RESULTS*>(pvResults));
-            break;
-        case BA_FUNCTIONS_MESSAGE_ONTHEMECONTROLWMCOMMAND:
-            hr = BalBaseBAFunctionsProcOnThemeControlWmCommand(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLWMCOMMAND_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLWMCOMMAND_RESULTS*>(pvResults));
-            break;
-        case BA_FUNCTIONS_MESSAGE_ONTHEMECONTROLWMNOTIFY:
-            hr = BalBaseBAFunctionsProcOnThemeControlWmNotify(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLWMNOTIFY_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLWMNOTIFY_RESULTS*>(pvResults));
-            break;
-        case BA_FUNCTIONS_MESSAGE_ONTHEMECONTROLLOADED:
-            hr = BalBaseBAFunctionsProcOnThemeControlLoaded(pBAFunctions, reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLLOADED_ARGS*>(pvArgs), reinterpret_cast<BA_FUNCTIONS_ONTHEMECONTROLLOADED_RESULTS*>(pvResults));
-            break;
-        }
-    }
-
-    return hr;
-}
+    );
diff --git a/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h b/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h
index ae7b2a93..30c75fb6 100644
--- a/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h
+++ b/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h
@@ -3,8 +3,6 @@
 #include <windows.h>
 #include <msiquery.h>
 
-#include "BootstrapperEngine.h"
-#include "BootstrapperApplication.h"
 #include "IBootstrapperEngine.h"
 #include "IBootstrapperApplication.h"
 
@@ -12,7 +10,9 @@
 #include "balinfo.h"
 #include "balretry.h"
 
-class CBalBaseBootstrapperApplication : public IBootstrapperApplication
+#define CBalBaseBootstrapperApplication CBootstrapperApplication
+
+class CBootstrapperApplication : public IBootstrapperApplication
 {
 public: // IUnknown
     virtual STDMETHODIMP QueryInterface(
@@ -65,8 +65,7 @@ public: // IBootstrapperApplication
     virtual STDMETHODIMP_(HRESULT) BAProc(
         __in BOOTSTRAPPER_APPLICATION_MESSAGE /*message*/,
         __in const LPVOID /*pvArgs*/,
-        __inout LPVOID /*pvResults*/,
-        __in_opt LPVOID /*pvContext*/
+        __inout LPVOID /*pvResults*/
         )
     {
         return E_NOTIMPL;
@@ -76,10 +75,35 @@ public: // IBootstrapperApplication
         __in BOOTSTRAPPER_APPLICATION_MESSAGE /*message*/,
         __in const LPVOID /*pvArgs*/,
         __inout LPVOID /*pvResults*/,
-        __inout HRESULT* /*phr*/,
-        __in_opt LPVOID /*pvContext*/
+        __inout HRESULT* /*phr*/
+        )
+    {
+    }
+
+    virtual STDMETHODIMP OnCreate(
+        __in IBootstrapperEngine* pEngine,
+        __in BOOTSTRAPPER_COMMAND* pCommand
+        )
+    {
+        HRESULT hr = S_OK;
+
+        m_commandDisplay = pCommand->display;
+
+        hr = BalInfoParseCommandLine(&m_BalInfoCommand, pCommand);
+        BalExitOnFailure(hr, "Failed to parse command line with balutil.");
+
+        pEngine->AddRef();
+        m_pEngine = pEngine;
+
+    LExit:
+        return hr;
+    }
+
+    virtual STDMETHODIMP OnDestroy(
+        __in BOOL /*fReload*/
         )
     {
+        return S_OK;
     }
 
     virtual STDMETHODIMP OnStartup()
@@ -429,7 +453,7 @@ public: // IBootstrapperApplication
         m_dwProgressPercentage = dwProgressPercentage;
         m_dwOverallProgressPercentage = dwOverallProgressPercentage;
 
-        if (BOOTSTRAPPER_DISPLAY_EMBEDDED == m_display)
+        if (BOOTSTRAPPER_DISPLAY_EMBEDDED == m_commandDisplay)
         {
             hr = m_pEngine->SendEmbeddedProgress(m_dwProgressPercentage, m_dwOverallProgressPercentage, &nResult);
             BalExitOnFailure(hr, "Failed to send embedded overall progress.");
@@ -463,7 +487,7 @@ public: // IBootstrapperApplication
     {
         BalRetryErrorOccurred(wzPackageId, dwCode);
 
-        if (BOOTSTRAPPER_DISPLAY_EMBEDDED == m_display)
+        if (BOOTSTRAPPER_DISPLAY_EMBEDDED == m_commandDisplay)
         {
             HRESULT hr = m_pEngine->SendEmbeddedError(dwCode, wzError, dwUIHint, pResult);
             if (FAILED(hr))
@@ -475,7 +499,7 @@ public: // IBootstrapperApplication
         {
             *pResult = IDCANCEL;
         }
-        else if (BOOTSTRAPPER_DISPLAY_FULL == m_display)
+        else if (BOOTSTRAPPER_DISPLAY_FULL == m_commandDisplay)
         {
             if (BOOTSTRAPPER_ERROR_TYPE_HTTP_AUTH_SERVER == errorType || BOOTSTRAPPER_ERROR_TYPE_HTTP_AUTH_PROXY == errorType)
             {
@@ -553,7 +577,7 @@ public: // IBootstrapperApplication
 
         // Send progress even though we don't update the numbers to at least give the caller an opportunity
         // to cancel.
-        if (BOOTSTRAPPER_DISPLAY_EMBEDDED == m_display)
+        if (BOOTSTRAPPER_DISPLAY_EMBEDDED == m_commandDisplay)
         {
             hr = m_pEngine->SendEmbeddedProgress(m_dwProgressPercentage, m_dwOverallProgressPercentage, &nResult);
             BalExitOnFailure(hr, "Failed to send embedded cache progress.");
@@ -733,7 +757,7 @@ public: // IBootstrapperApplication
 
         // Send progress even though we don't update the numbers to at least give the caller an opportunity
         // to cancel.
-        if (BOOTSTRAPPER_DISPLAY_EMBEDDED == m_display)
+        if (BOOTSTRAPPER_DISPLAY_EMBEDDED == m_commandDisplay)
         {
             hr = m_pEngine->SendEmbeddedProgress(m_dwProgressPercentage, m_dwOverallProgressPercentage, &nResult);
             BalExitOnFailure(hr, "Failed to send embedded execute progress.");
@@ -848,7 +872,7 @@ public: // IBootstrapperApplication
     {
         HRESULT hr = S_OK;
         BOOL fRestartRequired = BOOTSTRAPPER_APPLY_RESTART_REQUIRED == restart;
-        BOOL fShouldBlockRestart = BOOTSTRAPPER_DISPLAY_FULL <= m_display && BAL_INFO_RESTART_PROMPT >= m_BalInfoCommand.restart;
+        BOOL fShouldBlockRestart = BOOTSTRAPPER_DISPLAY_FULL <= m_commandDisplay && BAL_INFO_RESTART_PROMPT >= m_BalInfoCommand.restart;
 
         if (fRestartRequired && !fShouldBlockRestart)
         {
@@ -1050,20 +1074,6 @@ public: // IBootstrapperApplication
         return S_OK;
     }
 
-    virtual STDMETHODIMP OnSetUpdateBegin()
-    {
-        return S_OK;
-    }
-
-    virtual STDMETHODIMP OnSetUpdateComplete(
-        __in HRESULT /*hrStatus*/,
-        __in_z_opt LPCWSTR /*wzPreviousPackageId*/,
-        __in_z_opt LPCWSTR /*wzNewPackageId*/
-        )
-    {
-        return S_OK;
-    }
-
     virtual STDMETHODIMP OnPlanRestoreRelatedBundle(
         __in_z LPCWSTR /*wzBundleId*/,
         __in BOOTSTRAPPER_REQUEST_STATE /*recommendedState*/,
@@ -1127,22 +1137,6 @@ public: // IBootstrapperApplication
         return S_OK;
     }
 
-public: //CBalBaseBootstrapperApplication
-    virtual STDMETHODIMP Initialize(
-        __in const BOOTSTRAPPER_CREATE_ARGS* pCreateArgs
-        )
-    {
-        HRESULT hr = S_OK;
-
-        m_display = pCreateArgs->pCommand->display;
-
-        hr = BalInfoParseCommandLine(&m_BalInfoCommand, pCreateArgs->pCommand);
-        BalExitOnFailure(hr, "Failed to parse command line with balutil.");
-
-    LExit:
-        return hr;
-    }
-
 protected:
     //
     // PromptCancel - prompts the user to close (if not forced).
@@ -1195,16 +1189,14 @@ protected:
     }
 
     CBalBaseBootstrapperApplication(
-        __in IBootstrapperEngine* pEngine,
         __in DWORD dwRetryCount = 0,
         __in DWORD dwRetryTimeout = 1000
         )
     {
         m_cReferences = 1;
-        m_display = BOOTSTRAPPER_DISPLAY_UNKNOWN;
+        m_commandDisplay = BOOTSTRAPPER_DISPLAY_UNKNOWN;
 
-        pEngine->AddRef();
-        m_pEngine = pEngine;
+        m_pEngine = NULL;
 
         ::InitializeCriticalSection(&m_csCanceled);
         m_fCanceled = FALSE;
@@ -1230,12 +1222,12 @@ protected:
     CRITICAL_SECTION m_csCanceled;
     BOOL m_fCanceled;
 
+    IBootstrapperEngine* m_pEngine;
     BAL_INFO_COMMAND m_BalInfoCommand;
 
 private:
     long m_cReferences;
-    BOOTSTRAPPER_DISPLAY m_display;
-    IBootstrapperEngine* m_pEngine;
+    BOOTSTRAPPER_DISPLAY m_commandDisplay;
 
     BOOL m_fRollingBack;
 
diff --git a/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h b/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h
deleted file mode 100644
index 34739ba3..00000000
--- a/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h
+++ /dev/null
@@ -1,1045 +0,0 @@
-#pragma once
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-
-#include <windows.h>
-
-#include "BootstrapperEngine.h"
-#include "BootstrapperApplication.h"
-#include "IBootstrapperEngine.h"
-#include "IBootstrapperApplication.h"
-
-static HRESULT BalBaseBAProcOnDetectBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTBEGIN_ARGS* pArgs,
-    __inout BA_ONDETECTBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectBegin(pArgs->fCached, pArgs->registrationType, pArgs->cPackages, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnDetectComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTCOMPLETE_ARGS* pArgs,
-    __inout BA_ONDETECTCOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnDetectComplete(pArgs->hrStatus, pArgs->fEligibleForCleanup);
-}
-
-static HRESULT BalBaseBAProcOnPlanBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANBEGIN_ARGS* pArgs,
-    __inout BA_ONPLANBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanBegin(pArgs->cPackages, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnPlanComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANCOMPLETE_ARGS* pArgs,
-    __inout BA_ONPLANCOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnPlanComplete(pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnStartup(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONSTARTUP_ARGS* /*pArgs*/,
-    __inout BA_ONSTARTUP_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnStartup();
-}
-
-static HRESULT BalBaseBAProcOnShutdown(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONSHUTDOWN_ARGS* /*pArgs*/,
-    __inout BA_ONSHUTDOWN_RESULTS* pResults
-    )
-{
-    return pBA->OnShutdown(&pResults->action);
-}
-
-static HRESULT BalBaseBAProcOnDetectForwardCompatibleBundle(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_ARGS* pArgs,
-    __inout BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectForwardCompatibleBundle(pArgs->wzBundleId, pArgs->relationType, pArgs->wzBundleTag, pArgs->fPerMachine, pArgs->wzVersion, pArgs->fMissingFromCache, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnDetectUpdateBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTUPDATEBEGIN_ARGS* pArgs,
-    __inout BA_ONDETECTUPDATEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectUpdateBegin(pArgs->wzUpdateLocation, &pResults->fCancel, &pResults->fSkip);
-}
-
-static HRESULT BalBaseBAProcOnDetectUpdate(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTUPDATE_ARGS* pArgs,
-    __inout BA_ONDETECTUPDATE_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectUpdate(pArgs->wzUpdateLocation, pArgs->dw64Size, pArgs->wzHash, pArgs->hashAlgorithm, pArgs->wzVersion, pArgs->wzTitle, pArgs->wzSummary, pArgs->wzContentType, pArgs->wzContent, &pResults->fCancel, &pResults->fStopProcessingUpdates);
-}
-
-static HRESULT BalBaseBAProcOnDetectUpdateComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTUPDATECOMPLETE_ARGS* pArgs,
-    __inout BA_ONDETECTUPDATECOMPLETE_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectUpdateComplete(pArgs->hrStatus, &pResults->fIgnoreError);
-}
-
-static HRESULT BalBaseBAProcOnDetectRelatedBundle(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTRELATEDBUNDLE_ARGS* pArgs,
-    __inout BA_ONDETECTRELATEDBUNDLE_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectRelatedBundle(pArgs->wzBundleId, pArgs->relationType, pArgs->wzBundleTag, pArgs->fPerMachine, pArgs->wzVersion, pArgs->fMissingFromCache, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnDetectPackageBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTPACKAGEBEGIN_ARGS* pArgs,
-    __inout BA_ONDETECTPACKAGEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectPackageBegin(pArgs->wzPackageId, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnDetectCompatiblePackage(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTCOMPATIBLEMSIPACKAGE_ARGS* pArgs,
-    __inout BA_ONDETECTCOMPATIBLEMSIPACKAGE_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectCompatibleMsiPackage(pArgs->wzPackageId, pArgs->wzCompatiblePackageId, pArgs->wzCompatiblePackageVersion, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnDetectRelatedMsiPackage(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTRELATEDMSIPACKAGE_ARGS* pArgs,
-    __inout BA_ONDETECTRELATEDMSIPACKAGE_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectRelatedMsiPackage(pArgs->wzPackageId, pArgs->wzUpgradeCode, pArgs->wzProductCode, pArgs->fPerMachine, pArgs->wzVersion, pArgs->operation, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnDetectPatchTarget(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTPATCHTARGET_ARGS* pArgs,
-    __inout BA_ONDETECTPATCHTARGET_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectPatchTarget(pArgs->wzPackageId, pArgs->wzProductCode, pArgs->patchState, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnDetectMsiFeature(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTMSIFEATURE_ARGS* pArgs,
-    __inout BA_ONDETECTMSIFEATURE_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectMsiFeature(pArgs->wzPackageId, pArgs->wzFeatureId, pArgs->state, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnDetectPackageComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTPACKAGECOMPLETE_ARGS* pArgs,
-    __inout BA_ONDETECTPACKAGECOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnDetectPackageComplete(pArgs->wzPackageId, pArgs->hrStatus, pArgs->state, pArgs->fCached);
-}
-
-static HRESULT BalBaseBAProcOnPlanRelatedBundle(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANRELATEDBUNDLE_ARGS* pArgs,
-    __inout BA_ONPLANRELATEDBUNDLE_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanRelatedBundle(pArgs->wzBundleId, pArgs->recommendedState, &pResults->requestedState, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnPlanRollbackBoundary(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANROLLBACKBOUNDARY_ARGS* pArgs,
-    __inout BA_ONPLANROLLBACKBOUNDARY_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanRollbackBoundary(pArgs->wzRollbackBoundaryId, pArgs->fRecommendedTransaction, &pResults->fTransaction, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnPlanPackageBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANPACKAGEBEGIN_ARGS* pArgs,
-    __inout BA_ONPLANPACKAGEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanPackageBegin(pArgs->wzPackageId, pArgs->state, pArgs->fCached, pArgs->installCondition, pArgs->repairCondition, pArgs->recommendedState, pArgs->recommendedCacheType, &pResults->requestedState, &pResults->requestedCacheType, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnPlanCompatibleMsiPackageBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_ARGS* pArgs,
-    __inout BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanCompatibleMsiPackageBegin(pArgs->wzPackageId, pArgs->wzCompatiblePackageId, pArgs->wzCompatiblePackageVersion, pArgs->fRecommendedRemove, &pResults->fRequestRemove, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnPlanCompatibleMsiPackageComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_ARGS* pArgs,
-    __inout BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnPlanCompatibleMsiPackageComplete(pArgs->wzPackageId, pArgs->wzCompatiblePackageId, pArgs->hrStatus, pArgs->fRequestedRemove);
-}
-
-static HRESULT BalBaseBAProcOnPlanPatchTarget(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANPATCHTARGET_ARGS* pArgs,
-    __inout BA_ONPLANPATCHTARGET_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanPatchTarget(pArgs->wzPackageId, pArgs->wzProductCode, pArgs->recommendedState, &pResults->requestedState, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnPlanMsiFeature(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANMSIFEATURE_ARGS* pArgs,
-    __inout BA_ONPLANMSIFEATURE_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanMsiFeature(pArgs->wzPackageId, pArgs->wzFeatureId, pArgs->recommendedState, &pResults->requestedState, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnPlanPackageComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANPACKAGECOMPLETE_ARGS* pArgs,
-    __inout BA_ONPLANPACKAGECOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnPlanPackageComplete(pArgs->wzPackageId, pArgs->hrStatus, pArgs->requested);
-}
-
-static HRESULT BalBaseBAProcOnPlannedCompatiblePackage(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANNEDCOMPATIBLEPACKAGE_ARGS* pArgs,
-    __inout BA_ONPLANNEDCOMPATIBLEPACKAGE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnPlannedCompatiblePackage(pArgs->wzPackageId, pArgs->wzCompatiblePackageId, pArgs->fRemove);
-}
-
-static HRESULT BalBaseBAProcOnPlannedPackage(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANNEDPACKAGE_ARGS* pArgs,
-    __inout BA_ONPLANNEDPACKAGE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnPlannedPackage(pArgs->wzPackageId, pArgs->execute, pArgs->rollback, pArgs->fPlannedCache, pArgs->fPlannedUncache);
-}
-
-static HRESULT BalBaseBAProcOnApplyBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONAPPLYBEGIN_ARGS* pArgs,
-    __inout BA_ONAPPLYBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnApplyBegin(pArgs->dwPhaseCount, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnElevateBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONELEVATEBEGIN_ARGS* /*pArgs*/,
-    __inout BA_ONELEVATEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnElevateBegin(&pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnElevateComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONELEVATECOMPLETE_ARGS* pArgs,
-    __inout BA_ONELEVATECOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnElevateComplete(pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnProgress(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPROGRESS_ARGS* pArgs,
-    __inout BA_ONPROGRESS_RESULTS* pResults
-    )
-{
-    return pBA->OnProgress(pArgs->dwProgressPercentage, pArgs->dwOverallPercentage, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnError(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONERROR_ARGS* pArgs,
-    __inout BA_ONERROR_RESULTS* pResults
-    )
-{
-    return pBA->OnError(pArgs->errorType, pArgs->wzPackageId, pArgs->dwCode, pArgs->wzError, pArgs->dwUIHint, pArgs->cData, pArgs->rgwzData, pArgs->nRecommendation, &pResults->nResult);
-}
-
-static HRESULT BalBaseBAProcOnRegisterBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONREGISTERBEGIN_ARGS* pArgs,
-    __inout BA_ONREGISTERBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnRegisterBegin(pArgs->recommendedRegistrationType, &pResults->fCancel, &pResults->registrationType);
-}
-
-static HRESULT BalBaseBAProcOnRegisterComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONREGISTERCOMPLETE_ARGS* pArgs,
-    __inout BA_ONREGISTERCOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnRegisterComplete(pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnCacheBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEBEGIN_ARGS* /*pArgs*/,
-    __inout BA_ONCACHEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheBegin(&pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCachePackageBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEPACKAGEBEGIN_ARGS* pArgs,
-    __inout BA_ONCACHEPACKAGEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnCachePackageBegin(pArgs->wzPackageId, pArgs->cCachePayloads, pArgs->dw64PackageCacheSize, pArgs->fVital, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCacheAcquireBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEACQUIREBEGIN_ARGS* pArgs,
-    __inout BA_ONCACHEACQUIREBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheAcquireBegin(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->wzSource, pArgs->wzDownloadUrl, pArgs->wzPayloadContainerId, pArgs->recommendation, &pResults->action, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCacheAcquireProgress(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEACQUIREPROGRESS_ARGS* pArgs,
-    __inout BA_ONCACHEACQUIREPROGRESS_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheAcquireProgress(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->dw64Progress, pArgs->dw64Total, pArgs->dwOverallPercentage, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCacheAcquireResolving(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEACQUIRERESOLVING_ARGS* pArgs,
-    __inout BA_ONCACHEACQUIRERESOLVING_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheAcquireResolving(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->rgSearchPaths, pArgs->cSearchPaths, pArgs->fFoundLocal, pArgs->dwRecommendedSearchPath, pArgs->wzDownloadUrl, pArgs->wzPayloadContainerId, pArgs->recommendation, &pResults->dwChosenSearchPath, &pResults->action, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCacheAcquireComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEACQUIRECOMPLETE_ARGS* pArgs,
-    __inout BA_ONCACHEACQUIRECOMPLETE_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheAcquireComplete(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->hrStatus, pArgs->recommendation, &pResults->action);
-}
-
-static HRESULT BalBaseBAProcOnCacheVerifyBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEVERIFYBEGIN_ARGS* pArgs,
-    __inout BA_ONCACHEVERIFYBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheVerifyBegin(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCacheVerifyProgress(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEVERIFYPROGRESS_ARGS* pArgs,
-    __inout BA_ONCACHEVERIFYPROGRESS_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheVerifyProgress(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->dw64Progress, pArgs->dw64Total, pArgs->dwOverallPercentage, pArgs->verifyStep, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCacheVerifyComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEVERIFYCOMPLETE_ARGS* pArgs,
-    __inout BA_ONCACHEVERIFYCOMPLETE_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheVerifyComplete(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->hrStatus, pArgs->recommendation, &pResults->action);
-}
-
-static HRESULT BalBaseBAProcOnCachePackageComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEPACKAGECOMPLETE_ARGS* pArgs,
-    __inout BA_ONCACHEPACKAGECOMPLETE_RESULTS* pResults
-    )
-{
-    return pBA->OnCachePackageComplete(pArgs->wzPackageId, pArgs->hrStatus, pArgs->recommendation, &pResults->action);
-}
-
-static HRESULT BalBaseBAProcOnCacheComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHECOMPLETE_ARGS* pArgs,
-    __inout BA_ONCACHECOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnCacheComplete(pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnExecuteBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONEXECUTEBEGIN_ARGS* pArgs,
-    __inout BA_ONEXECUTEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnExecuteBegin(pArgs->cExecutingPackages, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnExecutePackageBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONEXECUTEPACKAGEBEGIN_ARGS* pArgs,
-    __inout BA_ONEXECUTEPACKAGEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnExecutePackageBegin(pArgs->wzPackageId, pArgs->fExecute, pArgs->action, pArgs->uiLevel, pArgs->fDisableExternalUiHandler, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnExecutePatchTarget(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONEXECUTEPATCHTARGET_ARGS* pArgs,
-    __inout BA_ONEXECUTEPATCHTARGET_RESULTS* pResults
-    )
-{
-    return pBA->OnExecutePatchTarget(pArgs->wzPackageId, pArgs->wzTargetProductCode, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnExecuteProgress(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONEXECUTEPROGRESS_ARGS* pArgs,
-    __inout BA_ONEXECUTEPROGRESS_RESULTS* pResults
-    )
-{
-    return pBA->OnExecuteProgress(pArgs->wzPackageId, pArgs->dwProgressPercentage, pArgs->dwOverallPercentage, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnExecuteMsiMessage(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONEXECUTEMSIMESSAGE_ARGS* pArgs,
-    __inout BA_ONEXECUTEMSIMESSAGE_RESULTS* pResults
-    )
-{
-    return pBA->OnExecuteMsiMessage(pArgs->wzPackageId, pArgs->messageType, pArgs->dwUIHint, pArgs->wzMessage, pArgs->cData, pArgs->rgwzData, pArgs->nRecommendation, &pResults->nResult);
-}
-
-static HRESULT BalBaseBAProcOnExecuteFilesInUse(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONEXECUTEFILESINUSE_ARGS* pArgs,
-    __inout BA_ONEXECUTEFILESINUSE_RESULTS* pResults
-    )
-{
-    return pBA->OnExecuteFilesInUse(pArgs->wzPackageId, pArgs->cFiles, pArgs->rgwzFiles, pArgs->nRecommendation, pArgs->source, &pResults->nResult);
-}
-
-static HRESULT BalBaseBAProcOnExecutePackageComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONEXECUTEPACKAGECOMPLETE_ARGS* pArgs,
-    __inout BA_ONEXECUTEPACKAGECOMPLETE_RESULTS* pResults
-    )
-{
-    return pBA->OnExecutePackageComplete(pArgs->wzPackageId, pArgs->hrStatus, pArgs->restart, pArgs->recommendation, &pResults->action);
-}
-
-static HRESULT BalBaseBAProcOnExecuteProcessCancel(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONEXECUTEPROCESSCANCEL_ARGS* pArgs,
-    __inout BA_ONEXECUTEPROCESSCANCEL_RESULTS* pResults
-    )
-{
-    return pBA->OnExecuteProcessCancel(pArgs->wzPackageId, pArgs->dwProcessId, pArgs->recommendation, &pResults->action);
-}
-
-static HRESULT BalBaseBAProcOnExecuteComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONEXECUTECOMPLETE_ARGS* pArgs,
-    __inout BA_ONEXECUTECOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnExecuteComplete(pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnUnregisterBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONUNREGISTERBEGIN_ARGS* pArgs,
-    __inout BA_ONUNREGISTERBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnUnregisterBegin(pArgs->recommendedRegistrationType, &pResults->registrationType);
-}
-
-static HRESULT BalBaseBAProcOnUnregisterComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONUNREGISTERCOMPLETE_ARGS* pArgs,
-    __inout BA_ONUNREGISTERCOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnUnregisterComplete(pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnApplyComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONAPPLYCOMPLETE_ARGS* pArgs,
-    __inout BA_ONAPPLYCOMPLETE_RESULTS* pResults
-    )
-{
-    return pBA->OnApplyComplete(pArgs->hrStatus, pArgs->restart, pArgs->recommendation, &pResults->action);
-}
-
-static HRESULT BalBaseBAProcOnLaunchApprovedExeBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONLAUNCHAPPROVEDEXEBEGIN_ARGS* /*pArgs*/,
-    __inout BA_ONLAUNCHAPPROVEDEXEBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnLaunchApprovedExeBegin(&pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnLaunchApprovedExeComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONLAUNCHAPPROVEDEXECOMPLETE_ARGS* pArgs,
-    __inout BA_ONLAUNCHAPPROVEDEXECOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnLaunchApprovedExeComplete(pArgs->hrStatus, pArgs->dwProcessId);
-}
-
-static HRESULT BalBaseBAProcOnPlanMsiPackage(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANMSIPACKAGE_ARGS* pArgs,
-    __inout BA_ONPLANMSIPACKAGE_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanMsiPackage(pArgs->wzPackageId, pArgs->fExecute, pArgs->action, pArgs->recommendedFileVersioning, &pResults->fCancel, &pResults->actionMsiProperty, &pResults->uiLevel, &pResults->fDisableExternalUiHandler, &pResults->fileVersioning);
-}
-
-static HRESULT BalBaseBAProcOnBeginMsiTransactionBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONBEGINMSITRANSACTIONBEGIN_ARGS* pArgs,
-    __inout BA_ONBEGINMSITRANSACTIONBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnBeginMsiTransactionBegin(pArgs->wzTransactionId, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnBeginMsiTransactionComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONBEGINMSITRANSACTIONCOMPLETE_ARGS* pArgs,
-    __inout BA_ONBEGINMSITRANSACTIONCOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnBeginMsiTransactionComplete(pArgs->wzTransactionId, pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnCommitMsiTransactionBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCOMMITMSITRANSACTIONBEGIN_ARGS* pArgs,
-    __inout BA_ONCOMMITMSITRANSACTIONBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnCommitMsiTransactionBegin(pArgs->wzTransactionId, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCommitMsiTransactionComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCOMMITMSITRANSACTIONCOMPLETE_ARGS* pArgs,
-    __inout BA_ONCOMMITMSITRANSACTIONCOMPLETE_RESULTS* pResults
-    )
-{
-    return pBA->OnCommitMsiTransactionComplete(pArgs->wzTransactionId, pArgs->hrStatus, pArgs->restart, pArgs->recommendation, &pResults->action);
-}
-
-static HRESULT BalBaseBAProcOnRollbackMsiTransactionBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONROLLBACKMSITRANSACTIONBEGIN_ARGS* pArgs,
-    __inout BA_ONROLLBACKMSITRANSACTIONBEGIN_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnRollbackMsiTransactionBegin(pArgs->wzTransactionId);
-}
-
-static HRESULT BalBaseBAProcOnRollbackMsiTransactionComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONROLLBACKMSITRANSACTIONCOMPLETE_ARGS* pArgs,
-    __inout BA_ONROLLBACKMSITRANSACTIONCOMPLETE_RESULTS* pResults
-    )
-{
-    return pBA->OnRollbackMsiTransactionComplete(pArgs->wzTransactionId, pArgs->hrStatus, pArgs->restart, pArgs->recommendation, &pResults->action);
-}
-
-static HRESULT BalBaseBAProcOnPauseAutomaticUpdatesBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPAUSEAUTOMATICUPDATESBEGIN_ARGS* /*pArgs*/,
-    __inout BA_ONPAUSEAUTOMATICUPDATESBEGIN_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnPauseAutomaticUpdatesBegin();
-}
-
-static HRESULT BalBaseBAProcOnPauseAutomaticUpdatesComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_ARGS* pArgs,
-    __inout BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnPauseAutomaticUpdatesComplete(pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnSystemRestorePointBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONSYSTEMRESTOREPOINTBEGIN_ARGS* /*pArgs*/,
-    __inout BA_ONSYSTEMRESTOREPOINTBEGIN_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnSystemRestorePointBegin();
-}
-
-static HRESULT BalBaseBAProcOnSystemRestorePointComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONSYSTEMRESTOREPOINTCOMPLETE_ARGS* pArgs,
-    __inout BA_ONSYSTEMRESTOREPOINTCOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnSystemRestorePointComplete(pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnPlanForwardCompatibleBundle(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANFORWARDCOMPATIBLEBUNDLE_ARGS* pArgs,
-    __inout BA_ONPLANFORWARDCOMPATIBLEBUNDLE_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanForwardCompatibleBundle(pArgs->wzBundleId, pArgs->relationType, pArgs->wzBundleTag, pArgs->fPerMachine, pArgs->wzVersion, pArgs->fRecommendedIgnoreBundle, &pResults->fCancel, &pResults->fIgnoreBundle);
-}
-
-static HRESULT BalBaseBAProcOnCacheContainerOrPayloadVerifyBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_ARGS* pArgs,
-    __inout BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheContainerOrPayloadVerifyBegin(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCacheContainerOrPayloadVerifyProgress(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_ARGS* pArgs,
-    __inout BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_RESULTS* pResults
-    )
-{
-    return pBA->OnCacheContainerOrPayloadVerifyProgress(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->dw64Progress, pArgs->dw64Total, pArgs->dwOverallPercentage, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCacheContainerOrPayloadVerifyComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_ARGS* pArgs,
-    __inout BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnCacheContainerOrPayloadVerifyComplete(pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnCachePayloadExtractBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEPAYLOADEXTRACTBEGIN_ARGS* pArgs,
-    __inout BA_ONCACHEPAYLOADEXTRACTBEGIN_RESULTS* pResults
-    )
-{
-    return pBA->OnCachePayloadExtractBegin(pArgs->wzContainerId, pArgs->wzPayloadId, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCachePayloadExtractProgress(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEPAYLOADEXTRACTPROGRESS_ARGS* pArgs,
-    __inout BA_ONCACHEPAYLOADEXTRACTPROGRESS_RESULTS* pResults
-    )
-{
-    return pBA->OnCachePayloadExtractProgress(pArgs->wzContainerId, pArgs->wzPayloadId, pArgs->dw64Progress, pArgs->dw64Total, pArgs->dwOverallPercentage, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCachePayloadExtractComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEPAYLOADEXTRACTCOMPLETE_ARGS* pArgs,
-    __inout BA_ONCACHEPAYLOADEXTRACTCOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnCachePayloadExtractComplete(pArgs->wzContainerId, pArgs->wzPayloadId, pArgs->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnSetUpdateBegin(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONSETUPDATEBEGIN_ARGS* /*pArgs*/,
-    __inout BA_ONSETUPDATEBEGIN_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnSetUpdateBegin();
-}
-
-static HRESULT BalBaseBAProcOnSetUpdateComplete(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONSETUPDATECOMPLETE_ARGS* pArgs,
-    __inout BA_ONSETUPDATECOMPLETE_RESULTS* /*pResults*/
-    )
-{
-    return pBA->OnSetUpdateComplete(pArgs->hrStatus, pArgs->wzPreviousPackageId, pArgs->wzNewPackageId);
-}
-
-static HRESULT BalBaseBAProcOnPlanRestoreRelatedBundle(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANRESTORERELATEDBUNDLE_ARGS* pArgs,
-    __inout BA_ONPLANRESTORERELATEDBUNDLE_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanRestoreRelatedBundle(pArgs->wzBundleId, pArgs->recommendedState, &pResults->requestedState, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnPlanRelatedBundleType(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONPLANRELATEDBUNDLETYPE_ARGS* pArgs,
-    __inout BA_ONPLANRELATEDBUNDLETYPE_RESULTS* pResults
-    )
-{
-    return pBA->OnPlanRelatedBundleType(pArgs->wzBundleId, pArgs->recommendedType, &pResults->requestedType, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnApplyDowngrade(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONAPPLYDOWNGRADE_ARGS* pArgs,
-    __inout BA_ONAPPLYDOWNGRADE_RESULTS* pResults
-    )
-{
-    return pBA->OnApplyDowngrade(pArgs->hrRecommended, &pResults->hrStatus);
-}
-
-static HRESULT BalBaseBAProcOnDetectRelatedBundlePackage(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONDETECTRELATEDBUNDLEPACKAGE_ARGS* pArgs,
-    __inout BA_ONDETECTRELATEDBUNDLEPACKAGE_RESULTS* pResults
-    )
-{
-    return pBA->OnDetectRelatedBundlePackage(pArgs->wzPackageId, pArgs->wzBundleId, pArgs->relationType, pArgs->fPerMachine, pArgs->wzVersion, &pResults->fCancel);
-}
-
-static HRESULT BalBaseBAProcOnCachePackageNonVitalValidationFailure(
-    __in IBootstrapperApplication* pBA,
-    __in BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_ARGS* pArgs,
-    __inout BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_RESULTS* pResults
-    )
-{
-    return pBA->OnCachePackageNonVitalValidationFailure(pArgs->wzPackageId, pArgs->hrStatus, pArgs->recommendation, &pResults->action);
-}
-
-/*******************************************************************
-BalBaseBootstrapperApplicationProc - requires pvContext to be of type IBootstrapperApplication.
-                                     Provides a default mapping between the new message based BA interface and
-                                     the old COM-based BA interface.
-
-*******************************************************************/
-static HRESULT WINAPI BalBaseBootstrapperApplicationProc(
-    __in BOOTSTRAPPER_APPLICATION_MESSAGE message,
-    __in const LPVOID pvArgs,
-    __inout LPVOID pvResults,
-    __in_opt LPVOID pvContext
-    )
-{
-    IBootstrapperApplication* pBA = reinterpret_cast<IBootstrapperApplication*>(pvContext);
-    HRESULT hr = pBA->BAProc(message, pvArgs, pvResults, pvContext);
-
-    if (E_NOTIMPL == hr)
-    {
-        switch (message)
-        {
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTBEGIN:
-            hr = BalBaseBAProcOnDetectBegin(pBA, reinterpret_cast<BA_ONDETECTBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPLETE:
-            hr = BalBaseBAProcOnDetectComplete(pBA, reinterpret_cast<BA_ONDETECTCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANBEGIN:
-            hr = BalBaseBAProcOnPlanBegin(pBA, reinterpret_cast<BA_ONPLANBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPLETE:
-            hr = BalBaseBAProcOnPlanComplete(pBA, reinterpret_cast<BA_ONPLANCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSTARTUP:
-            hr = BalBaseBAProcOnStartup(pBA, reinterpret_cast<BA_ONSTARTUP_ARGS*>(pvArgs), reinterpret_cast<BA_ONSTARTUP_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSHUTDOWN:
-            hr = BalBaseBAProcOnShutdown(pBA, reinterpret_cast<BA_ONSHUTDOWN_ARGS*>(pvArgs), reinterpret_cast<BA_ONSHUTDOWN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTFORWARDCOMPATIBLEBUNDLE:
-            hr = BalBaseBAProcOnDetectForwardCompatibleBundle(pBA, reinterpret_cast<BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATEBEGIN:
-            hr = BalBaseBAProcOnDetectUpdateBegin(pBA, reinterpret_cast<BA_ONDETECTUPDATEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTUPDATEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATE:
-            hr = BalBaseBAProcOnDetectUpdate(pBA, reinterpret_cast<BA_ONDETECTUPDATE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTUPDATE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATECOMPLETE:
-            hr = BalBaseBAProcOnDetectUpdateComplete(pBA, reinterpret_cast<BA_ONDETECTUPDATECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTUPDATECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLE:
-            hr = BalBaseBAProcOnDetectRelatedBundle(pBA, reinterpret_cast<BA_ONDETECTRELATEDBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTRELATEDBUNDLE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGEBEGIN:
-            hr = BalBaseBAProcOnDetectPackageBegin(pBA, reinterpret_cast<BA_ONDETECTPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTPACKAGEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDMSIPACKAGE:
-            hr = BalBaseBAProcOnDetectRelatedMsiPackage(pBA, reinterpret_cast<BA_ONDETECTRELATEDMSIPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTRELATEDMSIPACKAGE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPATCHTARGET:
-            hr = BalBaseBAProcOnDetectPatchTarget(pBA, reinterpret_cast<BA_ONDETECTPATCHTARGET_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTPATCHTARGET_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTMSIFEATURE:
-            hr = BalBaseBAProcOnDetectMsiFeature(pBA, reinterpret_cast<BA_ONDETECTMSIFEATURE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTMSIFEATURE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGECOMPLETE:
-            hr = BalBaseBAProcOnDetectPackageComplete(pBA, reinterpret_cast<BA_ONDETECTPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTPACKAGECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLE:
-            hr = BalBaseBAProcOnPlanRelatedBundle(pBA, reinterpret_cast<BA_ONPLANRELATEDBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANRELATEDBUNDLE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGEBEGIN:
-            hr = BalBaseBAProcOnPlanPackageBegin(pBA, reinterpret_cast<BA_ONPLANPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANPACKAGEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPATCHTARGET:
-            hr = BalBaseBAProcOnPlanPatchTarget(pBA, reinterpret_cast<BA_ONPLANPATCHTARGET_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANPATCHTARGET_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANMSIFEATURE:
-            hr = BalBaseBAProcOnPlanMsiFeature(pBA, reinterpret_cast<BA_ONPLANMSIFEATURE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANMSIFEATURE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGECOMPLETE:
-            hr = BalBaseBAProcOnPlanPackageComplete(pBA, reinterpret_cast<BA_ONPLANPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANPACKAGECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYBEGIN:
-            hr = BalBaseBAProcOnApplyBegin(pBA, reinterpret_cast<BA_ONAPPLYBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONAPPLYBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATEBEGIN:
-            hr = BalBaseBAProcOnElevateBegin(pBA, reinterpret_cast<BA_ONELEVATEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONELEVATEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATECOMPLETE:
-            hr = BalBaseBAProcOnElevateComplete(pBA, reinterpret_cast<BA_ONELEVATECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONELEVATECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPROGRESS:
-            hr = BalBaseBAProcOnProgress(pBA, reinterpret_cast<BA_ONPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONPROGRESS_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONERROR:
-            hr = BalBaseBAProcOnError(pBA, reinterpret_cast<BA_ONERROR_ARGS*>(pvArgs), reinterpret_cast<BA_ONERROR_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONREGISTERBEGIN:
-            hr = BalBaseBAProcOnRegisterBegin(pBA, reinterpret_cast<BA_ONREGISTERBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONREGISTERBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONREGISTERCOMPLETE:
-            hr = BalBaseBAProcOnRegisterComplete(pBA, reinterpret_cast<BA_ONREGISTERCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONREGISTERCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEBEGIN:
-            hr = BalBaseBAProcOnCacheBegin(pBA, reinterpret_cast<BA_ONCACHEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGEBEGIN:
-            hr = BalBaseBAProcOnCachePackageBegin(pBA, reinterpret_cast<BA_ONCACHEPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPACKAGEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIREBEGIN:
-            hr = BalBaseBAProcOnCacheAcquireBegin(pBA, reinterpret_cast<BA_ONCACHEACQUIREBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEACQUIREBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIREPROGRESS:
-            hr = BalBaseBAProcOnCacheAcquireProgress(pBA, reinterpret_cast<BA_ONCACHEACQUIREPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEACQUIREPROGRESS_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIRERESOLVING:
-            hr = BalBaseBAProcOnCacheAcquireResolving(pBA, reinterpret_cast<BA_ONCACHEACQUIRERESOLVING_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEACQUIRERESOLVING_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIRECOMPLETE:
-            hr = BalBaseBAProcOnCacheAcquireComplete(pBA, reinterpret_cast<BA_ONCACHEACQUIRECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEACQUIRECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYBEGIN:
-            hr = BalBaseBAProcOnCacheVerifyBegin(pBA, reinterpret_cast<BA_ONCACHEVERIFYBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEVERIFYBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYPROGRESS:
-            hr = BalBaseBAProcOnCacheVerifyProgress(pBA, reinterpret_cast<BA_ONCACHEVERIFYPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEVERIFYPROGRESS_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYCOMPLETE:
-            hr = BalBaseBAProcOnCacheVerifyComplete(pBA, reinterpret_cast<BA_ONCACHEVERIFYCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEVERIFYCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGECOMPLETE:
-            hr = BalBaseBAProcOnCachePackageComplete(pBA, reinterpret_cast<BA_ONCACHEPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPACKAGECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECOMPLETE:
-            hr = BalBaseBAProcOnCacheComplete(pBA, reinterpret_cast<BA_ONCACHECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEBEGIN:
-            hr = BalBaseBAProcOnExecuteBegin(pBA, reinterpret_cast<BA_ONEXECUTEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPACKAGEBEGIN:
-            hr = BalBaseBAProcOnExecutePackageBegin(pBA, reinterpret_cast<BA_ONEXECUTEPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPACKAGEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPATCHTARGET:
-            hr = BalBaseBAProcOnExecutePatchTarget(pBA, reinterpret_cast<BA_ONEXECUTEPATCHTARGET_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPATCHTARGET_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPROGRESS:
-            hr = BalBaseBAProcOnExecuteProgress(pBA, reinterpret_cast<BA_ONEXECUTEPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPROGRESS_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEMSIMESSAGE:
-            hr = BalBaseBAProcOnExecuteMsiMessage(pBA, reinterpret_cast<BA_ONEXECUTEMSIMESSAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEMSIMESSAGE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEFILESINUSE:
-            hr = BalBaseBAProcOnExecuteFilesInUse(pBA, reinterpret_cast<BA_ONEXECUTEFILESINUSE_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEFILESINUSE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPACKAGECOMPLETE:
-            hr = BalBaseBAProcOnExecutePackageComplete(pBA, reinterpret_cast<BA_ONEXECUTEPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPACKAGECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTECOMPLETE:
-            hr = BalBaseBAProcOnExecuteComplete(pBA, reinterpret_cast<BA_ONEXECUTECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONUNREGISTERBEGIN:
-            hr = BalBaseBAProcOnUnregisterBegin(pBA, reinterpret_cast<BA_ONUNREGISTERBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONUNREGISTERBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONUNREGISTERCOMPLETE:
-            hr = BalBaseBAProcOnUnregisterComplete(pBA, reinterpret_cast<BA_ONUNREGISTERCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONUNREGISTERCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYCOMPLETE:
-            hr = BalBaseBAProcOnApplyComplete(pBA, reinterpret_cast<BA_ONAPPLYCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONAPPLYCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONLAUNCHAPPROVEDEXEBEGIN:
-            hr = BalBaseBAProcOnLaunchApprovedExeBegin(pBA, reinterpret_cast<BA_ONLAUNCHAPPROVEDEXEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONLAUNCHAPPROVEDEXEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONLAUNCHAPPROVEDEXECOMPLETE:
-            hr = BalBaseBAProcOnLaunchApprovedExeComplete(pBA, reinterpret_cast<BA_ONLAUNCHAPPROVEDEXECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONLAUNCHAPPROVEDEXECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANMSIPACKAGE:
-            hr = BalBaseBAProcOnPlanMsiPackage(pBA, reinterpret_cast<BA_ONPLANMSIPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANMSIPACKAGE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONBEGINMSITRANSACTIONBEGIN:
-            hr = BalBaseBAProcOnBeginMsiTransactionBegin(pBA, reinterpret_cast<BA_ONBEGINMSITRANSACTIONBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONBEGINMSITRANSACTIONBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONBEGINMSITRANSACTIONCOMPLETE:
-            hr = BalBaseBAProcOnBeginMsiTransactionComplete(pBA, reinterpret_cast<BA_ONBEGINMSITRANSACTIONCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONBEGINMSITRANSACTIONCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCOMMITMSITRANSACTIONBEGIN:
-            hr = BalBaseBAProcOnCommitMsiTransactionBegin(pBA, reinterpret_cast<BA_ONCOMMITMSITRANSACTIONBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCOMMITMSITRANSACTIONBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCOMMITMSITRANSACTIONCOMPLETE:
-            hr = BalBaseBAProcOnCommitMsiTransactionComplete(pBA, reinterpret_cast<BA_ONCOMMITMSITRANSACTIONCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCOMMITMSITRANSACTIONCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONROLLBACKMSITRANSACTIONBEGIN:
-            hr = BalBaseBAProcOnRollbackMsiTransactionBegin(pBA, reinterpret_cast<BA_ONROLLBACKMSITRANSACTIONBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONROLLBACKMSITRANSACTIONBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONROLLBACKMSITRANSACTIONCOMPLETE:
-            hr = BalBaseBAProcOnRollbackMsiTransactionComplete(pBA, reinterpret_cast<BA_ONROLLBACKMSITRANSACTIONCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONROLLBACKMSITRANSACTIONCOMPLETE_RESULTS*>(pvResults));
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPAUSEAUTOMATICUPDATESBEGIN:
-            hr = BalBaseBAProcOnPauseAutomaticUpdatesBegin(pBA, reinterpret_cast<BA_ONPAUSEAUTOMATICUPDATESBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONPAUSEAUTOMATICUPDATESBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPAUSEAUTOMATICUPDATESCOMPLETE:
-            hr = BalBaseBAProcOnPauseAutomaticUpdatesComplete(pBA, reinterpret_cast<BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSYSTEMRESTOREPOINTBEGIN:
-            hr = BalBaseBAProcOnSystemRestorePointBegin(pBA, reinterpret_cast<BA_ONSYSTEMRESTOREPOINTBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONSYSTEMRESTOREPOINTBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSYSTEMRESTOREPOINTCOMPLETE:
-            hr = BalBaseBAProcOnSystemRestorePointComplete(pBA, reinterpret_cast<BA_ONSYSTEMRESTOREPOINTCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONSYSTEMRESTOREPOINTCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDPACKAGE:
-            hr = BalBaseBAProcOnPlannedPackage(pBA, reinterpret_cast<BA_ONPLANNEDPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANNEDPACKAGE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANFORWARDCOMPATIBLEBUNDLE:
-            hr = BalBaseBAProcOnPlanForwardCompatibleBundle(pBA, reinterpret_cast<BA_ONPLANFORWARDCOMPATIBLEBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANFORWARDCOMPATIBLEBUNDLE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYBEGIN:
-            hr = BalBaseBAProcOnCacheContainerOrPayloadVerifyBegin(pBA, reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS:
-            hr = BalBaseBAProcOnCacheContainerOrPayloadVerifyProgress(pBA, reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE:
-            hr = BalBaseBAProcOnCacheContainerOrPayloadVerifyComplete(pBA, reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTBEGIN:
-            hr = BalBaseBAProcOnCachePayloadExtractBegin(pBA, reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTPROGRESS:
-            hr = BalBaseBAProcOnCachePayloadExtractProgress(pBA, reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTPROGRESS_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTPROGRESS_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTCOMPLETE:
-            hr = BalBaseBAProcOnCachePayloadExtractComplete(pBA, reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTCOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPAYLOADEXTRACTCOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANROLLBACKBOUNDARY:
-            hr = BalBaseBAProcOnPlanRollbackBoundary(pBA, reinterpret_cast<BA_ONPLANROLLBACKBOUNDARY_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANROLLBACKBOUNDARY_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSETUPDATEBEGIN:
-            hr = BalBaseBAProcOnSetUpdateBegin(pBA, reinterpret_cast<BA_ONSETUPDATEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONSETUPDATEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSETUPDATECOMPLETE:
-            hr = BalBaseBAProcOnSetUpdateComplete(pBA, reinterpret_cast<BA_ONSETUPDATECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONSETUPDATECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPATIBLEMSIPACKAGE:
-            hr = BalBaseBAProcOnDetectCompatiblePackage(pBA, reinterpret_cast<BA_ONDETECTCOMPATIBLEMSIPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTCOMPATIBLEMSIPACKAGE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGEBEGIN:
-            hr = BalBaseBAProcOnPlanCompatibleMsiPackageBegin(pBA, reinterpret_cast<BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE:
-            hr = BalBaseBAProcOnPlanCompatibleMsiPackageComplete(pBA, reinterpret_cast<BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE:
-            hr = BalBaseBAProcOnPlannedCompatiblePackage(pBA, reinterpret_cast<BA_ONPLANNEDCOMPATIBLEPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANNEDCOMPATIBLEPACKAGE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRESTORERELATEDBUNDLE:
-            hr = BalBaseBAProcOnPlanRestoreRelatedBundle(pBA, reinterpret_cast<BA_ONPLANRESTORERELATEDBUNDLE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANRESTORERELATEDBUNDLE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLETYPE:
-            hr = BalBaseBAProcOnPlanRelatedBundleType(pBA, reinterpret_cast<BA_ONPLANRELATEDBUNDLETYPE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANRELATEDBUNDLETYPE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYDOWNGRADE:
-            hr = BalBaseBAProcOnApplyDowngrade(pBA, reinterpret_cast<BA_ONAPPLYDOWNGRADE_ARGS*>(pvArgs), reinterpret_cast<BA_ONAPPLYDOWNGRADE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPROCESSCANCEL:
-            hr = BalBaseBAProcOnExecuteProcessCancel(pBA, reinterpret_cast<BA_ONEXECUTEPROCESSCANCEL_ARGS*>(pvArgs), reinterpret_cast<BA_ONEXECUTEPROCESSCANCEL_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLEPACKAGE:
-            hr = BalBaseBAProcOnDetectRelatedBundlePackage(pBA, reinterpret_cast<BA_ONDETECTRELATEDBUNDLEPACKAGE_ARGS*>(pvArgs), reinterpret_cast<BA_ONDETECTRELATEDBUNDLEPACKAGE_RESULTS*>(pvResults));
-            break;
-        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGENONVITALVALIDATIONFAILURE:
-            hr = BalBaseBAProcOnCachePackageNonVitalValidationFailure(pBA, reinterpret_cast<BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_ARGS*>(pvArgs), reinterpret_cast<BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_RESULTS*>(pvResults));
-            break;
-        }
-    }
-
-    pBA->BAProcFallback(message, pvArgs, pvResults, &hr, pvContext);
-
-    return hr;
-}
diff --git a/src/api/burn/balutil/inc/IBAFunctions.h b/src/api/burn/balutil/inc/IBAFunctions.h
index bb911040..b0afabb3 100644
--- a/src/api/burn/balutil/inc/IBAFunctions.h
+++ b/src/api/burn/balutil/inc/IBAFunctions.h
@@ -2,6 +2,8 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
 
+#include "IBootstrapperApplication.h"
+
 DECLARE_INTERFACE_IID_(IBAFunctions, IBootstrapperApplication, "0FB445ED-17BD-49C7-BE19-479776F8AE96")
 {
     // OnThemeLoaded - Called after the BA finished loading all the controls for the theme.
diff --git a/src/api/burn/balutil/inc/IBootstrapperApplication.h b/src/api/burn/balutil/inc/IBootstrapperApplication.h
index faa211e4..6eb32ee6 100644
--- a/src/api/burn/balutil/inc/IBootstrapperApplication.h
+++ b/src/api/burn/balutil/inc/IBootstrapperApplication.h
@@ -1,6 +1,8 @@
 #pragma once
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
+#include <batypes.h>
+
 
 DECLARE_INTERFACE_IID_(IBootstrapperApplication, IUnknown, "53C31D56-49C0-426B-AB06-099D717C67FE")
 {
@@ -9,8 +11,7 @@ DECLARE_INTERFACE_IID_(IBootstrapperApplication, IUnknown, "53C31D56-49C0-426B-A
     STDMETHOD(BAProc)(
         __in BOOTSTRAPPER_APPLICATION_MESSAGE message,
         __in const LPVOID pvArgs,
-        __inout LPVOID pvResults,
-        __in_opt LPVOID pvContext
+        __inout LPVOID pvResults
         ) = 0;
 
     // BAProcFallback - The PFN_BOOTSTRAPPER_APPLICATION_PROC can call this method
@@ -20,10 +21,22 @@ DECLARE_INTERFACE_IID_(IBootstrapperApplication, IUnknown, "53C31D56-49C0-426B-A
         __in BOOTSTRAPPER_APPLICATION_MESSAGE message,
         __in const LPVOID pvArgs,
         __inout LPVOID pvResults,
-        __inout HRESULT* phr,
-        __in_opt LPVOID pvContext
+        __inout HRESULT* phr
+        ) = 0;
+
+    // OnCreate - called when the bootstrapper application is created.
+    //
+    virtual STDMETHODIMP OnCreate(
+        __in IBootstrapperEngine* pEngine,
+        __in BOOTSTRAPPER_COMMAND* pCommand
         ) = 0;
 
+    // OnDestroy - called before the bootstrapper application stops.
+    //
+    STDMETHOD(OnDestroy)(
+        __in BOOL fReload
+    ) = 0;
+
     // OnStartup - called when the engine is ready for the bootstrapper application to start.
     //
     STDMETHOD(OnStartup)() = 0;
@@ -688,14 +701,6 @@ DECLARE_INTERFACE_IID_(IBootstrapperApplication, IUnknown, "53C31D56-49C0-426B-A
         __in HRESULT hrStatus
         ) = 0;
 
-    STDMETHOD(OnSetUpdateBegin)() = 0;
-
-    STDMETHOD(OnSetUpdateComplete)(
-        __in HRESULT hrStatus,
-        __in_z_opt LPCWSTR wzPreviousPackageId,
-        __in_z_opt LPCWSTR wzNewPackageId
-        ) = 0;
-
     // OnPlanRestoreRelatedBundle - called when the engine begins planning an upgrade related bundle for restoring in case of failure.
     STDMETHOD(OnPlanRestoreRelatedBundle)(
         __in_z LPCWSTR wzBundleId,
diff --git a/src/api/burn/balutil/inc/IBootstrapperApplicationFactory.h b/src/api/burn/balutil/inc/IBootstrapperApplicationFactory.h
deleted file mode 100644
index fd603e50..00000000
--- a/src/api/burn/balutil/inc/IBootstrapperApplicationFactory.h
+++ /dev/null
@@ -1,13 +0,0 @@
-#pragma once
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-
-#include "precomp.h"
-
-DECLARE_INTERFACE_IID_(IBootstrapperApplicationFactory, IUnknown, "2965A12F-AC7B-43A0-85DF-E4B2168478A4")
-{
-    STDMETHOD(Create)(
-        __in const BOOTSTRAPPER_CREATE_ARGS* pArgs,
-        __inout BOOTSTRAPPER_CREATE_RESULTS *pResults
-        );
-};
diff --git a/src/api/burn/balutil/inc/IBootstrapperEngine.h b/src/api/burn/balutil/inc/IBootstrapperEngine.h
index bfa13997..3c1afb77 100644
--- a/src/api/burn/balutil/inc/IBootstrapperEngine.h
+++ b/src/api/burn/balutil/inc/IBootstrapperEngine.h
@@ -1,6 +1,7 @@
 #pragma once
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
+#include <baenginetypes.h>
 
 DECLARE_INTERFACE_IID_(IBootstrapperEngine, IUnknown, "6480D616-27A0-44D7-905B-81512C29C2FB")
 {
@@ -65,7 +66,8 @@ DECLARE_INTERFACE_IID_(IBootstrapperEngine, IUnknown, "6480D616-27A0-44D7-905B-8
         __in_z_opt LPCWSTR wzDownloadSource,
         __in DWORD64 qwSize,
         __in BOOTSTRAPPER_UPDATE_HASH_TYPE hashType,
-        __in_z_opt LPCWSTR wzHash
+        __in_z_opt LPCWSTR wzHash,
+        __in_z_opt LPCWSTR wzUpdatePackageId
         ) = 0;
 
     STDMETHOD(SetLocalSource)(
@@ -79,7 +81,8 @@ DECLARE_INTERFACE_IID_(IBootstrapperEngine, IUnknown, "6480D616-27A0-44D7-905B-8
         __in_z_opt LPCWSTR wzPayloadId,
         __in_z LPCWSTR wzUrl,
         __in_z_opt LPCWSTR wzUser,
-        __in_z_opt LPCWSTR wzPassword
+        __in_z_opt LPCWSTR wzPassword,
+        __in_z_opt LPCWSTR wzAuthorizationHeader
         ) = 0;
 
     STDMETHOD(SetVariableNumeric)(
@@ -128,7 +131,8 @@ DECLARE_INTERFACE_IID_(IBootstrapperEngine, IUnknown, "6480D616-27A0-44D7-905B-8
         ) = 0;
 
     STDMETHOD(SetUpdateSource)(
-        __in_z LPCWSTR wzUrl
+        __in_z LPCWSTR wzUrl,
+        __in_z_opt LPCWSTR wzAuthorizationHeader
         ) = 0;
 
     STDMETHOD(CompareVersions)(
@@ -143,5 +147,4 @@ DECLARE_INTERFACE_IID_(IBootstrapperEngine, IUnknown, "6480D616-27A0-44D7-905B-8
         __out_ecount_opt(*pcchValue) LPWSTR wzValue,
         __inout SIZE_T* pcchValue
         ) = 0;
-
 };
diff --git a/src/api/burn/balutil/inc/balinfo.h b/src/api/burn/balutil/inc/balinfo.h
index 7c607c44..234284f6 100644
--- a/src/api/burn/balutil/inc/balinfo.h
+++ b/src/api/burn/balutil/inc/balinfo.h
@@ -152,7 +152,6 @@ DAPI_(HRESULT) BalInfoAddRelatedBundleAsPackage(
 DAPI_(HRESULT) BalInfoAddUpdateBundleAsPackage(
     __in BAL_INFO_PACKAGES* pPackages,
     __in_z LPCWSTR wzId,
-    __in_z LPCWSTR wzPreviousId,
     __out_opt BAL_INFO_PACKAGE** ppPackage
     );
 
diff --git a/src/api/burn/balutil/inc/balutil.h b/src/api/burn/balutil/inc/balutil.h
index 36c165a3..4f8cb23d 100644
--- a/src/api/burn/balutil/inc/balutil.h
+++ b/src/api/burn/balutil/inc/balutil.h
@@ -39,28 +39,34 @@ const LPCWSTR BAL_MANIFEST_FILENAME = L"BootstrapperApplicationData.xml";
 
 static const HRESULT E_WIXSTDBA_CONDITION_FAILED = MAKE_HRESULT(SEVERITY_ERROR, FACILITY_WIX, 1);
 
-static const HRESULT E_MBAHOST_NET452_ON_WIN7RTM = MAKE_HRESULT(SEVERITY_ERROR, FACILITY_WIX, 1000);
-static const HRESULT E_DNCHOST_SCD_RUNTIME_FAILURE = MAKE_HRESULT(SEVERITY_ERROR, FACILITY_WIX, 1001);
 static const HRESULT E_PREREQBA_INFINITE_LOOP = MAKE_HRESULT(SEVERITY_ERROR, FACILITY_WIX, 1002);
 
 
 /*******************************************************************
- BalInitialize - remembers the engine interface to enable logging and
-                 other functions.
+ BootstrapperApplicationDebuggerCheck - allows bootstrapper application to
+        explicitly check whether a debugger should be attached to the boostrapper
+        application.
 
+ Note: Automatically called in BootstrapperApplicationRun().
 ********************************************************************/
-DAPI_(void) BalInitialize(
-    __in IBootstrapperEngine* pEngine
+DAPI_(VOID) BootstrapperApplicationDebuggerCheck();
+
+/*******************************************************************
+ BootstrapperApplicationRun - runs the IBootstrapperApplication until
+                              the application quits.
+
+********************************************************************/
+DAPI_(HRESULT) BootstrapperApplicationRun(
+    __in IBootstrapperApplication* pApplication
     );
 
 /*******************************************************************
- BalInitializeFromCreateArgs - convenience function to call BalBootstrapperEngineCreate
-                               then pass it along to BalInitialize.
+ BalInitialize - remembers the engine interface to enable logging and
+                 other functions.
 
 ********************************************************************/
-DAPI_(HRESULT) BalInitializeFromCreateArgs(
-    __in const BOOTSTRAPPER_CREATE_ARGS* pArgs,
-    __out_opt IBootstrapperEngine** ppEngine
+DAPI_(void) BalInitialize(
+    __in IBootstrapperEngine* pEngine
     );
 
 /*******************************************************************
@@ -292,7 +298,7 @@ DAPI_(HRESULT) BalLogErrorArgs(
     );
 
 /*******************************************************************
-BalLogId - logs a message with the engine with a string embedded in a 
+BalLogId - logs a message with the engine with a string embedded in a
            MESSAGETABLE resource.
 
 ********************************************************************/
diff --git a/src/api/burn/balutil/msg.cpp b/src/api/burn/balutil/msg.cpp
new file mode 100644
index 00000000..690108a5
--- /dev/null
+++ b/src/api/burn/balutil/msg.cpp
@@ -0,0 +1,5263 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+#include "precomp.h"
+
+static HRESULT OnApplyBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONAPPLYBEGIN_ARGS args = { };
+    BA_ONAPPLYBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnApplyBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwPhaseCount);
+    ExitOnFailure(hr, "Failed to read phase count of OnApplyBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnApplyBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnApplyBegin(args.dwPhaseCount, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnApplyBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnApplyBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnApplyBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnApplyComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONAPPLYCOMPLETE_ARGS args = { };
+    BA_ONAPPLYCOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnApplyComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnApplyComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.restart));
+    ExitOnFailure(hr, "Failed to read restart of OnApplyComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnApplyComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnApplyComplete results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnApplyComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnApplyComplete(args.hrStatus, args.restart, args.recommendation, &results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnApplyComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnApplyComplete struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnApplyComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnApplyDowngrade(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONAPPLYDOWNGRADE_ARGS args = { };
+    BA_ONAPPLYDOWNGRADE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnApplyDowngrade args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrRecommended));
+    ExitOnFailure(hr, "Failed to read recommended of OnApplyDowngrade args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnApplyDowngrade results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnApplyDowngrade results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYDOWNGRADE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnApplyDowngrade(args.hrRecommended, &results.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYDOWNGRADE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnApplyDowngrade failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnApplyDowngrade struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.hrStatus);
+    ExitOnFailure(hr, "Failed to write status of OnApplyDowngrade struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnBeginMsiTransactionBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONBEGINMSITRANSACTIONBEGIN_ARGS args = { };
+    BA_ONBEGINMSITRANSACTIONBEGIN_RESULTS results = { };
+    LPWSTR sczTransactionId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnBeginMsiTransactionBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczTransactionId);
+    ExitOnFailure(hr, "Failed to read recommended of OnBeginMsiTransactionBegin args.");
+
+    args.wzTransactionId = sczTransactionId;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnBeginMsiTransactionBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONBEGINMSITRANSACTIONBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnBeginMsiTransactionBegin(args.wzTransactionId, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONBEGINMSITRANSACTIONBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnBeginMsiTransactionBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnBeginMsiTransactionBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnBeginMsiTransactionBegin struct.");
+
+LExit:
+    ReleaseStr(sczTransactionId);
+    return hr;
+}
+
+static HRESULT OnBeginMsiTransactionComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONBEGINMSITRANSACTIONCOMPLETE_ARGS args = { };
+    BA_ONBEGINMSITRANSACTIONCOMPLETE_RESULTS results = { };
+    LPWSTR sczTransactionId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnBeginMsiTransactionComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczTransactionId);
+    ExitOnFailure(hr, "Failed to read transaction id of OnBeginMsiTransactionComplete args.");
+
+    args.wzTransactionId = sczTransactionId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnBeginMsiTransactionComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnBeginMsiTransactionComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONBEGINMSITRANSACTIONCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnBeginMsiTransactionComplete(args.wzTransactionId, args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONBEGINMSITRANSACTIONCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnBeginMsiTransactionComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnBeginMsiTransactionComplete struct.");
+
+LExit:
+    ReleaseStr(sczTransactionId);
+    return hr;
+}
+
+static HRESULT OnCacheAcquireBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEACQUIREBEGIN_ARGS args = { };
+    BA_ONCACHEACQUIREBEGIN_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+    LPWSTR sczSource = NULL;
+    LPWSTR sczDownloadUrl = NULL;
+    LPWSTR sczPayloadContainerId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheAcquireBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheAcquireBegin args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheAcquireBegin args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczSource);
+    ExitOnFailure(hr, "Failed to read source of OnCacheAcquireBegin args.");
+
+    args.wzSource = sczSource;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczDownloadUrl);
+    ExitOnFailure(hr, "Failed to read download url of OnCacheAcquireBegin args.");
+
+    args.wzDownloadUrl = sczDownloadUrl;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadContainerId);
+    ExitOnFailure(hr, "Failed to read payload container id of OnCacheAcquireBegin args.");
+
+    args.wzPayloadContainerId = sczPayloadContainerId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnCacheAcquireBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheAcquireBegin results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnCacheAcquireBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIREBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheAcquireBegin(args.wzPackageOrContainerId, args.wzPayloadId, args.wzSource, args.wzDownloadUrl, args.wzPayloadContainerId, args.recommendation, &results.action, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIREBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheAcquireBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheAcquireBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCacheAcquireBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnCacheAcquireBegin struct.");
+
+LExit:
+    ReleaseStr(sczPayloadContainerId);
+    ReleaseStr(sczDownloadUrl);
+    ReleaseStr(sczSource);
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+    return hr;
+}
+
+static HRESULT OnCacheAcquireComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEACQUIRECOMPLETE_ARGS args = { };
+    BA_ONCACHEACQUIRECOMPLETE_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheAcquireComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheAcquireComplete args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheAcquireComplete args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnCacheAcquireComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnCacheAcquireComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheAcquireComplete results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnCacheAcquireComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIRECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheAcquireComplete(args.wzPackageOrContainerId, args.wzPayloadId, args.hrStatus, args.recommendation, &results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIRECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheAcquireComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheAcquireComplete struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnCacheAcquireComplete struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+    return hr;
+}
+
+static HRESULT OnCacheAcquireProgress(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEACQUIREPROGRESS_ARGS args = { };
+    BA_ONCACHEACQUIREPROGRESS_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheAcquireProgress args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheAcquireProgress args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheAcquireProgress args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64Progress);
+    ExitOnFailure(hr, "Failed to read progress of OnCacheAcquireProgress args.");
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64Total);
+    ExitOnFailure(hr, "Failed to read total progress of OnCacheAcquireProgress args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwOverallPercentage);
+    ExitOnFailure(hr, "Failed to read overall percentage of OnCacheAcquireProgress args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheAcquireProgress results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIREPROGRESS, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheAcquireProgress(args.wzPackageOrContainerId, args.wzPayloadId, args.dw64Progress, args.dw64Total, args.dwOverallPercentage, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIREPROGRESS, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheAcquireProgress failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheAcquireProgress struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCacheAcquireProgress struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+    return hr;
+}
+
+static HRESULT OnCacheAcquireResolving(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEACQUIRERESOLVING_ARGS args = { };
+    BA_ONCACHEACQUIRERESOLVING_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+    DWORD cSearchPaths = 0;
+    LPWSTR* rgsczSearchPaths = NULL;
+    LPWSTR sczDownloadUrl = NULL;
+    LPWSTR sczPayloadContainerId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheAcquireResolving args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheAcquireResolving args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheAcquireResolving args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, &cSearchPaths);
+    ExitOnFailure(hr, "Failed to read overall percentage of OnCacheAcquireResolving args.");
+
+    if (cSearchPaths)
+    {
+        rgsczSearchPaths = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cSearchPaths, TRUE));
+        ExitOnNull(rgsczSearchPaths, hr, E_OUTOFMEMORY, "Failed to allocate memory for search paths of OnCacheAcquireResolving args.");
+
+        for (DWORD i = 0; i < cSearchPaths; ++i)
+        {
+            hr = BuffReaderReadString(pReaderArgs, &rgsczSearchPaths[i]);
+            ExitOnFailure(hr, "Failed to read search path[%u] of OnCacheAcquireResolving args.", i);
+        }
+    }
+
+    args.cSearchPaths = cSearchPaths;
+    args.rgSearchPaths = const_cast<LPCWSTR*>(rgsczSearchPaths);
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fFoundLocal));
+    ExitOnFailure(hr, "Failed to read found local of OnCacheAcquireResolving args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwRecommendedSearchPath);
+    ExitOnFailure(hr, "Failed to read recommended search path of OnCacheAcquireResolving args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczDownloadUrl);
+    ExitOnFailure(hr, "Failed to read download url of OnCacheAcquireResolving args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadContainerId);
+    ExitOnFailure(hr, "Failed to read payload container id of OnCacheAcquireResolving args.");
+
+    args.wzPayloadContainerId = sczPayloadContainerId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendedation of OnCacheAcquireResolving args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheAcquireResolving results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwChosenSearchPath);
+    ExitOnFailure(hr, "Failed to read chosen search path of OnCacheAcquireResolving results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnCacheAcquireResolving results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIRERESOLVING, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheAcquireResolving(args.wzPackageOrContainerId, args.wzPayloadId, args.rgSearchPaths, args.cSearchPaths, args.fFoundLocal, args.dwRecommendedSearchPath, args.wzDownloadUrl, args.wzPayloadContainerId, args.recommendation, &results.dwChosenSearchPath, &results.action, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIRERESOLVING, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheAcquireResolving failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheAcquireResolving struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.dwChosenSearchPath);
+    ExitOnFailure(hr, "Failed to write chosen search path of OnCacheAcquireResolving struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnCacheAcquireResolving struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCacheAcquireResolving struct.");
+
+LExit:
+    for (DWORD i = 0; rgsczSearchPaths && i < cSearchPaths; ++i)
+    {
+        ReleaseStr(rgsczSearchPaths[i]);
+    }
+    ReleaseMem(rgsczSearchPaths);
+
+    ReleaseStr(sczPayloadContainerId);
+    ReleaseStr(sczDownloadUrl);
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+
+    return hr;
+}
+
+static HRESULT OnCacheBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEBEGIN_ARGS args = { };
+    BA_ONCACHEBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheBegin(&results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCacheBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnCacheComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHECOMPLETE_ARGS args = { };
+    BA_ONCACHECOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnCacheComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheComplete(args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnCacheContainerOrPayloadVerifyBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_ARGS args = { };
+    BA_ONCACHECONTAINERORPAYLOADVERIFYBEGIN_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheContainerOrPayloadVerifyBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheContainerOrPayloadVerifyBegin args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheContainerOrPayloadVerifyBegin args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheContainerOrPayloadVerifyBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheContainerOrPayloadVerifyBegin(args.wzPackageOrContainerId, args.wzPayloadId, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheContainerOrPayloadVerifyBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheContainerOrPayloadVerifyBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCacheContainerOrPayloadVerifyBegin struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+    return hr;
+}
+
+static HRESULT OnCacheContainerOrPayloadVerifyComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_ARGS args = { };
+    BA_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheContainerOrPayloadVerifyComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheContainerOrPayloadVerifyComplete args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheContainerOrPayloadVerifyComplete args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnCacheContainerOrPayloadVerifyComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheContainerOrPayloadVerifyComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheContainerOrPayloadVerifyComplete(args.wzPackageOrContainerId, args.wzPayloadId, args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheContainerOrPayloadVerifyComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheContainerOrPayloadVerifyComplete struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+    return hr;
+}
+
+static HRESULT OnCacheContainerOrPayloadVerifyProgress(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_ARGS args = { };
+    BA_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheContainerOrPayloadVerifyProgress args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheContainerOrPayloadVerifyProgress args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheContainerOrPayloadVerifyProgress args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64Progress);
+    ExitOnFailure(hr, "Failed to read progress of OnCacheContainerOrPayloadVerifyProgress args.");
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64Total);
+    ExitOnFailure(hr, "Failed to read total progress of OnCacheContainerOrPayloadVerifyProgress args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwOverallPercentage);
+    ExitOnFailure(hr, "Failed to read overall percentage of OnCacheContainerOrPayloadVerifyProgress args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheContainerOrPayloadVerifyProgress results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheContainerOrPayloadVerifyProgress(args.wzPackageOrContainerId, args.wzPayloadId, args.dw64Progress, args.dw64Total, args.dwOverallPercentage, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheContainerOrPayloadVerifyProgress failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheContainerOrPayloadVerifyProgress struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCacheContainerOrPayloadVerifyProgress struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+    return hr;
+}
+
+static HRESULT OnCachePackageBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEPACKAGEBEGIN_ARGS args = { };
+    BA_ONCACHEPACKAGEBEGIN_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePackageBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnCachePackageBegin args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.cCachePayloads);
+    ExitOnFailure(hr, "Failed to read count of cached payloads of OnCachePackageBegin args.");
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64PackageCacheSize);
+    ExitOnFailure(hr, "Failed to read package cache size of OnCachePackageBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fVital));
+    ExitOnFailure(hr, "Failed to read vital of OnCachePackageBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePackageBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCachePackageBegin(args.wzPackageId, args.cCachePayloads, args.dw64PackageCacheSize, args.fVital, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCachePackageBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCachePackageBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCachePackageBegin struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnCachePackageComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEPACKAGECOMPLETE_ARGS args = { };
+    BA_ONCACHEPACKAGECOMPLETE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePackageComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnCachePackageComplete args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnCachePackageComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnCachePackageComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePackageComplete results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnCachePackageComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCachePackageComplete(args.wzPackageId, args.hrStatus, args.recommendation, &results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCachePackageComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCachePackageComplete struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnCachePackageComplete struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnCachePackageNonVitalValidationFailure(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_ARGS args = { };
+    BA_ONCACHEPACKAGENONVITALVALIDATIONFAILURE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePackageNonVitalValidationFailure args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnCachePackageNonVitalValidationFailure args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnCachePackageNonVitalValidationFailure args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnCachePackageNonVitalValidationFailure args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePackageNonVitalValidationFailure results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnCachePackageNonVitalValidationFailure results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGENONVITALVALIDATIONFAILURE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCachePackageNonVitalValidationFailure(args.wzPackageId, args.hrStatus, args.recommendation, &results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGENONVITALVALIDATIONFAILURE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCachePackageNonVitalValidationFailure failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCachePackageNonVitalValidationFailure struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnCachePackageNonVitalValidationFailure struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnCachePayloadExtractBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEPAYLOADEXTRACTBEGIN_ARGS args = { };
+    BA_ONCACHEPAYLOADEXTRACTBEGIN_RESULTS results = { };
+    LPWSTR sczContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePayloadExtractBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczContainerId);
+    ExitOnFailure(hr, "Failed to read container id of OnCachePayloadExtractBegin args.");
+
+    args.wzContainerId = sczContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCachePayloadExtractBegin args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePayloadExtractBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCachePayloadExtractBegin(args.wzContainerId, args.wzPayloadId, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCachePayloadExtractBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCachePayloadExtractBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCachePayloadExtractBegin struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczContainerId);
+    return hr;
+}
+
+static HRESULT OnCachePayloadExtractComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEPAYLOADEXTRACTCOMPLETE_ARGS args = { };
+    BA_ONCACHEPAYLOADEXTRACTCOMPLETE_RESULTS results = { };
+    LPWSTR sczContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePayloadExtractComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczContainerId);
+    ExitOnFailure(hr, "Failed to read container id of OnCachePayloadExtractComplete args.");
+
+    args.wzContainerId = sczContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCachePayloadExtractComplete args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnCachePayloadExtractComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePayloadExtractComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCachePayloadExtractComplete(args.wzContainerId, args.wzPayloadId, args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCachePayloadExtractComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCachePayloadExtractComplete struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczContainerId);
+    return hr;
+}
+
+static HRESULT OnCachePayloadExtractProgress(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEPAYLOADEXTRACTPROGRESS_ARGS args = { };
+    BA_ONCACHEPAYLOADEXTRACTPROGRESS_RESULTS results = { };
+    LPWSTR sczContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePayloadExtractProgress args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczContainerId);
+    ExitOnFailure(hr, "Failed to read container id of OnCachePayloadExtractProgress args.");
+
+    args.wzContainerId = sczContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCachePayloadExtractProgress args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64Progress);
+    ExitOnFailure(hr, "Failed to read progress of OnCachePayloadExtractProgress args.");
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64Total);
+    ExitOnFailure(hr, "Failed to read total progress of OnCachePayloadExtractProgress args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwOverallPercentage);
+    ExitOnFailure(hr, "Failed to read overall percentage of OnCachePayloadExtractProgress args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCachePayloadExtractProgress results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTPROGRESS, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCachePayloadExtractProgress(args.wzContainerId, args.wzPayloadId, args.dw64Progress, args.dw64Total, args.dwOverallPercentage, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTPROGRESS, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCachePayloadExtractProgress failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCachePayloadExtractProgress struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCachePayloadExtractProgress struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczContainerId);
+    return hr;
+}
+
+static HRESULT OnCacheVerifyBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEVERIFYBEGIN_ARGS args = { };
+    BA_ONCACHEVERIFYBEGIN_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheVerifyBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheVerifyBegin args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheVerifyBegin args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheVerifyBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheVerifyBegin(args.wzPackageOrContainerId, args.wzPayloadId, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheVerifyBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheVerifyBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCacheVerifyBegin struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+    return hr;
+}
+
+static HRESULT OnCacheVerifyComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEVERIFYCOMPLETE_ARGS args = { };
+    BA_ONCACHEVERIFYCOMPLETE_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheVerifyComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheVerifyComplete args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheVerifyComplete args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnCacheVerifyComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnCacheVerifyComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheVerifyComplete results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read API version of OnCacheVerifyComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheVerifyComplete(args.wzPackageOrContainerId, args.wzPayloadId, args.hrStatus, args.recommendation, &results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheVerifyComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheVerifyComplete struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnCacheVerifyComplete struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+    return hr;
+}
+
+static HRESULT OnCacheVerifyProgress(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCACHEVERIFYPROGRESS_ARGS args = { };
+    BA_ONCACHEVERIFYPROGRESS_RESULTS results = { };
+    LPWSTR sczPackageOrContainerId = NULL;
+    LPWSTR sczPayloadId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheVerifyProgress args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageOrContainerId);
+    ExitOnFailure(hr, "Failed to read package or container id of OnCacheVerifyProgress args.");
+
+    args.wzPackageOrContainerId = sczPackageOrContainerId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPayloadId);
+    ExitOnFailure(hr, "Failed to read payload id of OnCacheVerifyProgress args.");
+
+    args.wzPayloadId = sczPayloadId;
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64Progress);
+    ExitOnFailure(hr, "Failed to read progress of OnCacheVerifyProgress args.");
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64Total);
+    ExitOnFailure(hr, "Failed to read total progress of OnCacheVerifyProgress args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwOverallPercentage);
+    ExitOnFailure(hr, "Failed to read overall percentage of OnCacheVerifyProgress args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.verifyStep));
+    ExitOnFailure(hr, "Failed to read verify step of OnCacheVerifyProgress args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCacheVerifyProgress results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYPROGRESS, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCacheVerifyProgress(args.wzPackageOrContainerId, args.wzPayloadId, args.dw64Progress, args.dw64Total, args.dwOverallPercentage, args.verifyStep, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYPROGRESS, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCacheVerifyProgress failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCacheVerifyProgress struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCacheVerifyProgress struct.");
+
+LExit:
+    ReleaseStr(sczPayloadId);
+    ReleaseStr(sczPackageOrContainerId);
+    return hr;
+}
+
+static HRESULT OnCommitMsiTransactionBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCOMMITMSITRANSACTIONBEGIN_ARGS args = { };
+    BA_ONCOMMITMSITRANSACTIONBEGIN_RESULTS results = { };
+    LPWSTR sczTransactionId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCommitMsiTransactionBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczTransactionId);
+    ExitOnFailure(hr, "Failed to read transaction id of OnCommitMsiTransactionBegin args.");
+
+    args.wzTransactionId = sczTransactionId;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCommitMsiTransactionBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCOMMITMSITRANSACTIONBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCommitMsiTransactionBegin(args.wzTransactionId, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCOMMITMSITRANSACTIONBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCommitMsiTransactionBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCommitMsiTransactionBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnCommitMsiTransactionBegin struct.");
+
+LExit:
+    ReleaseStr(sczTransactionId);
+    return hr;
+}
+
+static HRESULT OnCommitMsiTransactionComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCOMMITMSITRANSACTIONCOMPLETE_ARGS args = { };
+    BA_ONCOMMITMSITRANSACTIONCOMPLETE_RESULTS results = { };
+    LPWSTR sczTransactionId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCommitMsiTransactionComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczTransactionId);
+    ExitOnFailure(hr, "Failed to read transaction id of OnCommitMsiTransactionComplete args.");
+
+    args.wzTransactionId = sczTransactionId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnCommitMsiTransactionComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.restart));
+    ExitOnFailure(hr, "Failed to read restart of OnCommitMsiTransactionComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnCommitMsiTransactionComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCommitMsiTransactionComplete results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnCommitMsiTransactionComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCOMMITMSITRANSACTIONCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCommitMsiTransactionComplete(args.wzTransactionId, args.hrStatus, args.restart, args.recommendation, &results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCOMMITMSITRANSACTIONCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCommitMsiTransactionComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnCommitMsiTransactionComplete struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnCommitMsiTransactionComplete struct.");
+
+LExit:
+    ReleaseStr(sczTransactionId);
+    return hr;
+}
+
+static HRESULT OnCreate(
+    __in IBootstrapperApplication* pApplication,
+    __in IBootstrapperEngine* pEngine,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONCREATE_ARGS args = { };
+    BA_ONCREATE_RESULTS results = { };
+    LPWSTR sczCommandLine = NULL;
+    LPWSTR sczLayoutDirectory = NULL;
+    LPWSTR sczBootstrapperWorkingFolder = NULL;
+    LPWSTR sczBootstrapperApplicationDataPath = NULL;
+    DWORD64 dw64 = 0;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCreate args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.command.cbSize));
+    ExitOnFailure(hr, "Failed to size of of OnCreate args command.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.command.action));
+    ExitOnFailure(hr, "Failed to read action of OnCreate args command.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.command.display));
+    ExitOnFailure(hr, "Failed to read action of OnCreate args command.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczCommandLine);
+    ExitOnFailure(hr, "Failed to read command-line of OnCreate args command.");
+
+    args.command.wzCommandLine = sczCommandLine;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.command.nCmdShow));
+    ExitOnFailure(hr, "Failed to read show command of OnCreate args command.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.command.resumeType));
+    ExitOnFailure(hr, "Failed to read resume type of OnCreate args command.");
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &dw64);
+    ExitOnFailure(hr, "Failed to read splash screen handle of OnCreate args command.");
+
+    args.command.hwndSplashScreen = reinterpret_cast<HWND>(dw64);
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.command.relationType));
+    ExitOnFailure(hr, "Failed to read relation type of OnCreate args command.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.command.fPassthrough));
+    ExitOnFailure(hr, "Failed to read passthrough of OnCreate args command.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczLayoutDirectory);
+    ExitOnFailure(hr, "Failed to read command-line of OnCreate args command.");
+
+    args.command.wzLayoutDirectory = sczLayoutDirectory;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBootstrapperWorkingFolder);
+    ExitOnFailure(hr, "Failed to read command-line of OnCreate args command.");
+
+    args.command.wzBootstrapperWorkingFolder = sczBootstrapperWorkingFolder;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBootstrapperApplicationDataPath);
+    ExitOnFailure(hr, "Failed to read command-line of OnCreate args command.");
+
+    args.command.wzBootstrapperApplicationDataPath = sczBootstrapperApplicationDataPath;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnCreate results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCREATE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnCreate(pEngine, &args.command);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCREATE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnCreate failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of BA_ONCREATE_RESULTS struct.");
+
+LExit:
+    ReleaseStr(sczBootstrapperApplicationDataPath);
+    ReleaseStr(sczBootstrapperWorkingFolder);
+    ReleaseStr(sczLayoutDirectory);
+    ReleaseStr(sczCommandLine);
+
+    return hr;
+}
+
+static HRESULT OnDestroy(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDESTROY_ARGS args = { };
+    BA_ONDESTROY_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDestroy args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fReload));
+    ExitOnFailure(hr, "Failed to read reload of OnDestroy args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDestroy results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDESTROY, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDestroy(args.fReload);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDESTROY, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDestroy failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDestroy struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnDetectBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTBEGIN_ARGS args = { };
+    BA_ONDETECTBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.registrationType));
+    ExitOnFailure(hr, "Failed to read registration type of OnDetectBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.cPackages);
+    ExitOnFailure(hr, "Failed to read package count of OnDetectBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fCached));
+    ExitOnFailure(hr, "Failed to read cached of OnDetectBegin args.");
+
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectBegin(args.fCached, args.registrationType, args.cPackages, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnDetectCompatibleMsiPackage(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTCOMPATIBLEMSIPACKAGE_ARGS args = { };
+    BA_ONDETECTCOMPATIBLEMSIPACKAGE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczCompatiblePackageId = NULL;
+    LPWSTR sczCompatiblePackageVersion = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectCompatibleMsiPackage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnDetectCompatibleMsiPackage args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczCompatiblePackageId);
+    ExitOnFailure(hr, "Failed to read compatible package id of OnDetectCompatibleMsiPackage args.");
+
+    args.wzCompatiblePackageId = sczCompatiblePackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczCompatiblePackageVersion);
+    ExitOnFailure(hr, "Failed to read compatible package version of OnDetectCompatibleMsiPackage args.");
+
+    args.wzCompatiblePackageVersion = sczCompatiblePackageVersion;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectCompatibleMsiPackage results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPATIBLEMSIPACKAGE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectCompatibleMsiPackage(args.wzPackageId, args.wzCompatiblePackageId, args.wzCompatiblePackageVersion, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPATIBLEMSIPACKAGE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectCompatibleMsiPackage failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectCompatibleMsiPackage struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectCompatibleMsiPackage struct.");
+
+LExit:
+    ReleaseStr(sczCompatiblePackageVersion);
+    ReleaseStr(sczCompatiblePackageId);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnDetectComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTCOMPLETE_ARGS args = { };
+    BA_ONDETECTCOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnDetectComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fEligibleForCleanup));
+    ExitOnFailure(hr, "Failed to read eligible for cleanup of OnDetectComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectComplete(args.hrStatus, args.fEligibleForCleanup);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnDetectForwardCompatibleBundle(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_ARGS args = { };
+    BA_ONDETECTFORWARDCOMPATIBLEBUNDLE_RESULTS results = { };
+    LPWSTR sczBundleId = NULL;
+    LPWSTR sczBundleTag = NULL;
+    LPWSTR sczVersion = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectForwardCompatibleBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleId);
+    ExitOnFailure(hr, "Failed to read bundle id of OnDetectForwardCompatibleBundle args.");
+
+    args.wzBundleId = sczBundleId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.relationType));
+    ExitOnFailure(hr, "Failed to read relation type of OnDetectForwardCompatibleBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleTag);
+    ExitOnFailure(hr, "Failed to read bundle tag of OnDetectForwardCompatibleBundle args.");
+
+    args.wzBundleTag = sczBundleTag;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fPerMachine));
+    ExitOnFailure(hr, "Failed to read per-machine of OnDetectForwardCompatibleBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczVersion);
+    ExitOnFailure(hr, "Failed to read version of OnDetectForwardCompatibleBundle args.");
+
+    args.wzVersion = sczVersion;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fMissingFromCache));
+    ExitOnFailure(hr, "Failed to read missing from cache of OnDetectForwardCompatibleBundle args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectForwardCompatibleBundle results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTFORWARDCOMPATIBLEBUNDLE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectForwardCompatibleBundle(args.wzBundleId, args.relationType, args.wzBundleTag, args.fPerMachine, args.wzVersion, args.fMissingFromCache, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTFORWARDCOMPATIBLEBUNDLE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectForwardCompatibleBundle failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectForwardCompatibleBundle struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectForwardCompatibleBundle struct.");
+
+LExit:
+    ReleaseStr(sczVersion);
+    ReleaseStr(sczBundleTag);
+    ReleaseStr(sczBundleId);
+    return hr;
+}
+
+static HRESULT OnDetectMsiFeature(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTMSIFEATURE_ARGS args = { };
+    BA_ONDETECTMSIFEATURE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczFeatureId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectMsiFeature args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnDetectMsiFeature args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczFeatureId);
+    ExitOnFailure(hr, "Failed to read feature id of OnDetectMsiFeature args.");
+
+    args.wzFeatureId = sczFeatureId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.state));
+    ExitOnFailure(hr, "Failed to read state of OnDetectMsiFeature args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectMsiFeature results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTMSIFEATURE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectMsiFeature(args.wzPackageId, args.wzFeatureId, args.state, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTMSIFEATURE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectMsiFeature failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectMsiFeature struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectMsiFeature struct.");
+
+LExit:
+    ReleaseStr(sczFeatureId);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnDetectPackageBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTPACKAGEBEGIN_ARGS args = { };
+    BA_ONDETECTPACKAGEBEGIN_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectPackageBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnDetectPackageBegin args.");
+
+    args.wzPackageId = sczPackageId;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectPackageBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectPackageBegin(args.wzPackageId, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectPackageBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectPackageBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectPackageBegin struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnDetectPackageComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTPACKAGECOMPLETE_ARGS args = { };
+    BA_ONDETECTPACKAGECOMPLETE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectPackageComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnDetectPackageComplete args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnDetectPackageComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.state));
+    ExitOnFailure(hr, "Failed to read state of OnDetectPackageComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fCached));
+    ExitOnFailure(hr, "Failed to read cached of OnDetectPackageComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectPackageComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectPackageComplete(args.wzPackageId, args.hrStatus, args.state, args.fCached);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectPackageComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectPackageComplete struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnDetectRelatedBundle(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTRELATEDBUNDLE_ARGS args = { };
+    BA_ONDETECTRELATEDBUNDLE_RESULTS results = { };
+    LPWSTR sczBundleId = NULL;
+    LPWSTR sczBundleTag = NULL;
+    LPWSTR sczVersion = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectRelatedBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleId);
+    ExitOnFailure(hr, "Failed to read bundle id of OnDetectRelatedBundle args.");
+
+    args.wzBundleId = sczBundleId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.relationType));
+    ExitOnFailure(hr, "Failed to read relation type of OnDetectRelatedBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleTag);
+    ExitOnFailure(hr, "Failed to read bundle tag of OnDetectRelatedBundle args.");
+
+    args.wzBundleTag = sczBundleTag;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fPerMachine));
+    ExitOnFailure(hr, "Failed to read per-machine of OnDetectRelatedBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczVersion);
+    ExitOnFailure(hr, "Failed to read version of OnDetectRelatedBundle args.");
+
+    args.wzVersion = sczVersion;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fMissingFromCache));
+    ExitOnFailure(hr, "Failed to read missing from cache of OnDetectRelatedBundle args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectRelatedBundle results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectRelatedBundle(args.wzBundleId, args.relationType, args.wzBundleTag, args.fPerMachine, args.wzVersion, args.fMissingFromCache, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectRelatedBundle failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectRelatedBundle struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectRelatedBundle struct.");
+
+LExit:
+    ReleaseStr(sczVersion);
+    ReleaseStr(sczBundleTag);
+    ReleaseStr(sczBundleId);
+    return hr;
+}
+
+static HRESULT OnDetectRelatedBundlePackage(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTRELATEDBUNDLEPACKAGE_ARGS args = { };
+    BA_ONDETECTRELATEDBUNDLEPACKAGE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczBundleId = NULL;
+    LPWSTR sczVersion = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectRelatedBundlePackage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnDetectRelatedBundlePackage args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleId);
+    ExitOnFailure(hr, "Failed to read bundle id of OnDetectRelatedBundlePackage args.");
+
+    args.wzBundleId = sczBundleId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.relationType));
+    ExitOnFailure(hr, "Failed to read relation type of OnDetectRelatedBundlePackage args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fPerMachine));
+    ExitOnFailure(hr, "Failed to read per-machine of OnDetectRelatedBundlePackage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczVersion);
+    ExitOnFailure(hr, "Failed to read version of OnDetectRelatedBundlePackage args.");
+
+    args.wzVersion = sczVersion;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectRelatedBundlePackage results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLEPACKAGE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectRelatedBundlePackage(args.wzPackageId, args.wzBundleId, args.relationType, args.fPerMachine, args.wzVersion, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLEPACKAGE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectRelatedBundlePackage failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectRelatedBundlePackage struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectRelatedBundlePackage struct.");
+
+LExit:
+    ReleaseStr(sczVersion);
+    ReleaseStr(sczBundleId);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnDetectRelatedMsiPackage(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTRELATEDMSIPACKAGE_ARGS args = { };
+    BA_ONDETECTRELATEDMSIPACKAGE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczUpgradeCode = NULL;
+    LPWSTR sczProductCode = NULL;
+    LPWSTR sczVersion = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectRelatedMsiPackage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnDetectRelatedMsiPackage args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczUpgradeCode);
+    ExitOnFailure(hr, "Failed to read upgrade code of OnDetectRelatedMsiPackage args.");
+
+    args.wzUpgradeCode = sczUpgradeCode;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczProductCode);
+    ExitOnFailure(hr, "Failed to read product code of OnDetectRelatedMsiPackage args.");
+
+    args.wzProductCode = sczProductCode;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fPerMachine));
+    ExitOnFailure(hr, "Failed to read per-machine of OnDetectRelatedMsiPackage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczVersion);
+    ExitOnFailure(hr, "Failed to read version of OnDetectRelatedMsiPackage args.");
+
+    args.wzVersion = sczVersion;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.operation));
+    ExitOnFailure(hr, "Failed to read per-machine of OnDetectRelatedMsiPackage args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectRelatedMsiPackage results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDMSIPACKAGE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectRelatedMsiPackage(args.wzPackageId, args.wzUpgradeCode, args.wzProductCode, args.fPerMachine, args.wzVersion, args.operation, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDMSIPACKAGE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectRelatedMsiPackage failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectRelatedMsiPackage struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectRelatedMsiPackage struct.");
+
+LExit:
+    ReleaseStr(sczVersion);
+    ReleaseStr(sczProductCode);
+    ReleaseStr(sczUpgradeCode);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnDetectPatchTarget(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTPATCHTARGET_ARGS args = { };
+    BA_ONDETECTPATCHTARGET_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczProductCode = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectPatchTarget args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnDetectPatchTarget args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczProductCode);
+    ExitOnFailure(hr, "Failed to read product code of OnDetectPatchTarget args.");
+
+    args.wzProductCode = sczProductCode;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.patchState));
+    ExitOnFailure(hr, "Failed to read patch state of OnDetectPatchTarget args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectPatchTarget results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPATCHTARGET, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectPatchTarget(args.wzPackageId, args.wzProductCode, args.patchState, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPATCHTARGET, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectPatchTarget failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectPatchTarget struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectPatchTarget struct.");
+
+LExit:
+    ReleaseStr(sczProductCode);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnDetectUpdate(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTUPDATE_ARGS args = { };
+    BA_ONDETECTUPDATE_RESULTS results = { };
+    LPWSTR sczUpdateLocation = NULL;
+    LPWSTR sczHash = NULL;
+    LPWSTR sczVersion = NULL;
+    LPWSTR sczTitle = NULL;
+    LPWSTR sczSummary = NULL;
+    LPWSTR sczContentType = NULL;
+    LPWSTR sczContent = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectUpdate args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczUpdateLocation);
+    ExitOnFailure(hr, "Failed to read update location of OnDetectUpdate args.");
+
+    args.wzUpdateLocation = sczUpdateLocation;
+
+    hr = BuffReaderReadNumber64(pReaderArgs, &args.dw64Size);
+    ExitOnFailure(hr, "Failed to read update size of OnDetectUpdate args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczHash);
+    ExitOnFailure(hr, "Failed to read hash of OnDetectUpdate args.");
+
+    args.wzHash = sczHash;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hashAlgorithm));
+    ExitOnFailure(hr, "Failed to read hash algorithm of OnDetectUpdate args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczVersion);
+    ExitOnFailure(hr, "Failed to read version of OnDetectUpdate args.");
+
+    args.wzVersion = sczVersion;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczTitle);
+    ExitOnFailure(hr, "Failed to read title of OnDetectUpdate args.");
+
+    args.wzTitle = sczTitle;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczSummary);
+    ExitOnFailure(hr, "Failed to read summary of OnDetectUpdate args.");
+
+    args.wzSummary = sczSummary;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczContentType);
+    ExitOnFailure(hr, "Failed to read content type of OnDetectUpdate args.");
+
+    args.wzContentType = sczContentType;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczContent);
+    ExitOnFailure(hr, "Failed to read content of OnDetectUpdate args.");
+
+    args.wzContent = sczContent;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectUpdate results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.fStopProcessingUpdates));
+    ExitOnFailure(hr, "Failed to read stop processing updates of OnDetectUpdate results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectUpdate(args.wzUpdateLocation, args.dw64Size, args.wzHash, args.hashAlgorithm, args.wzVersion, args.wzTitle, args.wzSummary, args.wzContentType, args.wzContent, &results.fCancel, &results.fStopProcessingUpdates);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectUpdate failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectUpdate struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectUpdate struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fStopProcessingUpdates);
+    ExitOnFailure(hr, "Failed to write stop processing updates of OnDetectUpdate struct.");
+
+LExit:
+    ReleaseStr(sczContent);
+    ReleaseStr(sczContentType);
+    ReleaseStr(sczSummary);
+    ReleaseStr(sczTitle);
+    ReleaseStr(sczVersion);
+    ReleaseStr(sczHash);
+    ReleaseStr(sczUpdateLocation);
+    return hr;
+}
+
+static HRESULT OnDetectUpdateBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTUPDATEBEGIN_ARGS args = { };
+    BA_ONDETECTUPDATEBEGIN_RESULTS results = { };
+    LPWSTR sczUpdateLocation = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectUpdateBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczUpdateLocation);
+    ExitOnFailure(hr, "Failed to read update location of OnDetectUpdateBegin args.");
+
+    args.wzUpdateLocation = sczUpdateLocation;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectUpdateBegin results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.fSkip));
+    ExitOnFailure(hr, "Failed to read skip of OnDetectUpdateBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectUpdateBegin(args.wzUpdateLocation, &results.fCancel, &results.fSkip);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectUpdateBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectUpdateBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnDetectUpdateBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fSkip);
+    ExitOnFailure(hr, "Failed to write skip processing updates of OnDetectUpdateBegin struct.");
+
+LExit:
+    ReleaseStr(sczUpdateLocation);
+    return hr;
+}
+
+
+static HRESULT OnDetectUpdateComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONDETECTUPDATECOMPLETE_ARGS args = { };
+    BA_ONDETECTUPDATECOMPLETE_RESULTS results = { };
+    LPWSTR sczUpdateLocation = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectUpdateComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnDetectUpdateComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnDetectUpdateComplete results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.fIgnoreError));
+    ExitOnFailure(hr, "Failed to read ignore error of OnDetectUpdateComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnDetectUpdateComplete(args.hrStatus, &results.fIgnoreError);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnDetectUpdateComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnDetectUpdateComplete struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fIgnoreError);
+    ExitOnFailure(hr, "Failed to write ignore error of OnDetectUpdateComplete struct.");
+
+LExit:
+    ReleaseStr(sczUpdateLocation);
+    return hr;
+}
+
+static HRESULT OnElevateBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONELEVATEBEGIN_ARGS args = { };
+    BA_ONELEVATEBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnElevateBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnElevateBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnElevateBegin(&results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnElevateBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnElevateBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnElevateBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnElevateComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONELEVATECOMPLETE_ARGS args = { };
+    BA_ONELEVATECOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnElevateComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnElevateComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnElevateComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnElevateComplete(args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnElevateComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnElevateComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnError(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONERROR_ARGS args = { };
+    BA_ONERROR_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczError = NULL;
+    DWORD cData = 0;
+    LPWSTR* rgsczData = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnError args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.errorType));
+    ExitOnFailure(hr, "Failed to read error type of OnError args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnError args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwCode);
+    ExitOnFailure(hr, "Failed to read code of OnError args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczError);
+    ExitOnFailure(hr, "Failed to read error of OnError args.");
+
+    args.wzError = sczError;
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwUIHint);
+    ExitOnFailure(hr, "Failed to read UI hint of OnError args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &cData);
+    ExitOnFailure(hr, "Failed to read count of data of OnError args.");
+
+    if (cData)
+    {
+        rgsczData = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cData, TRUE));
+        ExitOnNull(rgsczData, hr, E_OUTOFMEMORY, "Failed to allocate memory for data of OnError args.");
+
+        for (DWORD i = 0; i < cData; ++i)
+        {
+            hr = BuffReaderReadString(pReaderArgs, &rgsczData[i]);
+            ExitOnFailure(hr, "Failed to read search path[%u] of OnError args.", i);
+        }
+    }
+
+    args.cData = cData;
+    args.rgwzData = const_cast<LPCWSTR*>(rgsczData);
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.nRecommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnError args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnError results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.nResult));
+    ExitOnFailure(hr, "Failed to read cancel of OnError results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONERROR, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnError(args.errorType, args.wzPackageId, args.dwCode, args.wzError, args.dwUIHint, args.cData, args.rgwzData, args.nRecommendation, &results.nResult);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONERROR, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnError failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnError struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.nResult);
+    ExitOnFailure(hr, "Failed to write result of OnError struct.");
+
+LExit:
+    for (DWORD i = 0; rgsczData && i < cData; ++i)
+    {
+        ReleaseStr(rgsczData[i]);
+    }
+    ReleaseMem(rgsczData);
+
+    ReleaseStr(sczError);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnExecuteBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONEXECUTEBEGIN_ARGS args = { };
+    BA_ONEXECUTEBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.cExecutingPackages);
+    ExitOnFailure(hr, "Failed to executing packages of OnExecuteBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnExecuteBegin(args.cExecutingPackages, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnExecuteBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnExecuteBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnExecuteBegin struct.");
+
+LExit:
+    return hr;
+}
+
+
+static HRESULT OnExecuteComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONEXECUTECOMPLETE_ARGS args = { };
+    BA_ONEXECUTECOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to status of OnExecuteComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnExecuteComplete(args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnExecuteComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnExecuteComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnExecuteFilesInUse(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONEXECUTEFILESINUSE_ARGS args = { };
+    BA_ONEXECUTEFILESINUSE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    DWORD cFiles = 0;
+    LPWSTR* rgsczFiles = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteFilesInUse args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnExecuteFilesInUse args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, &cFiles);
+    ExitOnFailure(hr, "Failed to read count of files of OnExecuteFilesInUse args.");
+
+    if (cFiles)
+    {
+        rgsczFiles = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cFiles, TRUE));
+        ExitOnNull(rgsczFiles, hr, E_OUTOFMEMORY, "Failed to allocate memory for files of OnExecuteFilesInUse args.");
+
+        for (DWORD i = 0; i < cFiles; ++i)
+        {
+            hr = BuffReaderReadString(pReaderArgs, &rgsczFiles[i]);
+            ExitOnFailure(hr, "Failed to read file[%u] of OnExecuteFilesInUse args.", i);
+        }
+    }
+
+    args.cFiles = cFiles;
+    args.rgwzFiles = const_cast<LPCWSTR*>(rgsczFiles);
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.nRecommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnExecuteFilesInUse args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.source));
+    ExitOnFailure(hr, "Failed to read source of OnExecuteFilesInUse args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteFilesInUse results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.nResult));
+    ExitOnFailure(hr, "Failed to read result of OnExecuteFilesInUse results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEFILESINUSE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnExecuteFilesInUse(args.wzPackageId, args.cFiles, args.rgwzFiles, args.nRecommendation, args.source, &results.nResult);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEFILESINUSE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnExecuteFilesInUse failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnExecuteFilesInUse struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.nResult);
+    ExitOnFailure(hr, "Failed to write result of OnExecuteFilesInUse struct.");
+
+LExit:
+    for (DWORD i = 0; rgsczFiles && i < cFiles; ++i)
+    {
+        ReleaseStr(rgsczFiles[i]);
+    }
+    ReleaseMem(rgsczFiles);
+
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnExecuteMsiMessage(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONEXECUTEMSIMESSAGE_ARGS args = { };
+    BA_ONEXECUTEMSIMESSAGE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczMessage = NULL;
+    DWORD cData = 0;
+    LPWSTR* rgsczData = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteMsiMessage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnExecuteMsiMessage args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.messageType));
+    ExitOnFailure(hr, "Failed to read messageType of OnExecuteMsiMessage args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwUIHint);
+    ExitOnFailure(hr, "Failed to read UI hint of OnExecuteMsiMessage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczMessage);
+    ExitOnFailure(hr, "Failed to read message of OnExecuteMsiMessage args.");
+
+    args.wzMessage = sczMessage;
+
+    hr = BuffReaderReadNumber(pReaderArgs, &cData);
+    ExitOnFailure(hr, "Failed to read count of files of OnExecuteMsiMessage args.");
+
+    if (cData)
+    {
+        rgsczData = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cData, TRUE));
+        ExitOnNull(rgsczData, hr, E_OUTOFMEMORY, "Failed to allocate memory for data of OnExecuteMsiMessage args.");
+
+        for (DWORD i = 0; i < cData; ++i)
+        {
+            hr = BuffReaderReadString(pReaderArgs, &rgsczData[i]);
+            ExitOnFailure(hr, "Failed to read data[%u] of OnExecuteMsiMessage args.", i);
+        }
+    }
+
+    args.cData = cData;
+    args.rgwzData = const_cast<LPCWSTR*>(rgsczData);
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.nRecommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnExecuteMsiMessage args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteMsiMessage results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.nResult));
+    ExitOnFailure(hr, "Failed to read result of OnExecuteMsiMessage results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEMSIMESSAGE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnExecuteMsiMessage(args.wzPackageId, args.messageType, args.dwUIHint, args.wzMessage, args.cData, args.rgwzData, args.nRecommendation, &results.nResult);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEMSIMESSAGE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnExecuteMsiMessage failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnExecuteMsiMessage struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.nResult);
+    ExitOnFailure(hr, "Failed to write result of OnExecuteMsiMessage struct.");
+
+LExit:
+    for (DWORD i = 0; rgsczData && i < cData; ++i)
+    {
+        ReleaseStr(rgsczData[i]);
+    }
+    ReleaseMem(rgsczData);
+
+    ReleaseStr(sczMessage);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnExecutePackageBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONEXECUTEPACKAGEBEGIN_ARGS args = { };
+    BA_ONEXECUTEPACKAGEBEGIN_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecutePackageBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnExecutePackageBegin args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fExecute));
+    ExitOnFailure(hr, "Failed to read execute of OnExecutePackageBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.action));
+    ExitOnFailure(hr, "Failed to read action of OnExecutePackageBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.uiLevel));
+    ExitOnFailure(hr, "Failed to read UI level of OnExecutePackageBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fDisableExternalUiHandler));
+    ExitOnFailure(hr, "Failed to read disable external UI handler of OnExecutePackageBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecutePackageBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPACKAGEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnExecutePackageBegin(args.wzPackageId, args.fExecute, args.action, args.uiLevel, args.fDisableExternalUiHandler, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPACKAGEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnExecutePackageBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnExecutePackageBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnExecutePackageBegin struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnExecutePackageComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONEXECUTEPACKAGECOMPLETE_ARGS args = { };
+    BA_ONEXECUTEPACKAGECOMPLETE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecutePackageComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnExecutePackageComplete args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnExecutePackageComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.restart));
+    ExitOnFailure(hr, "Failed to read restart of OnExecutePackageComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnExecutePackageComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecutePackageComplete results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnExecutePackageComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPACKAGECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnExecutePackageComplete(args.wzPackageId, args.hrStatus, args.restart, args.recommendation, &results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPACKAGECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnExecutePackageComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnExecutePackageComplete struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnExecutePackageComplete struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnExecutePatchTarget(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONEXECUTEPATCHTARGET_ARGS args = { };
+    BA_ONEXECUTEPATCHTARGET_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczTargetProductCode = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecutePatchTarget args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnExecutePatchTarget args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczTargetProductCode);
+    ExitOnFailure(hr, "Failed to read target product code of OnExecutePatchTarget args.");
+
+    args.wzTargetProductCode = sczTargetProductCode;
+
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecutePatchTarget results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPATCHTARGET, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnExecutePatchTarget(args.wzPackageId, args.wzTargetProductCode, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPATCHTARGET, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnExecutePatchTarget failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnExecutePatchTarget struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnExecutePatchTarget struct.");
+
+LExit:
+    ReleaseStr(sczTargetProductCode);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnExecuteProcessCancel(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONEXECUTEPROCESSCANCEL_ARGS args = { };
+    BA_ONEXECUTEPROCESSCANCEL_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteProcessCancel args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnExecuteProcessCancel args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwProcessId);
+    ExitOnFailure(hr, "Failed to read process id of OnExecuteProcessCancel args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnExecuteProcessCancel args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteProcessCancel results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnExecuteProcessCancel results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPROCESSCANCEL, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnExecuteProcessCancel(args.wzPackageId, args.dwProcessId, args.recommendation, &results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPROCESSCANCEL, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnExecuteProcessCancel failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnExecuteProcessCancel struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnExecuteProcessCancel struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnExecuteProgress(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONEXECUTEPROGRESS_ARGS args = { };
+    BA_ONEXECUTEPROGRESS_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteProgress args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnExecuteProgress args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwProgressPercentage);
+    ExitOnFailure(hr, "Failed to read progress of OnExecuteProgress args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwOverallPercentage);
+    ExitOnFailure(hr, "Failed to read overall progress of OnExecuteProgress args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnExecuteProgress results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPROGRESS, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnExecuteProgress(args.wzPackageId, args.dwProgressPercentage, args.dwOverallPercentage, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPROGRESS, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnExecuteProgress failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnExecuteProgress struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnExecuteProgress struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnLaunchApprovedExeBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONLAUNCHAPPROVEDEXEBEGIN_ARGS args = { };
+    BA_ONLAUNCHAPPROVEDEXEBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnLaunchApprovedExeBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnLaunchApprovedExeBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONLAUNCHAPPROVEDEXEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnLaunchApprovedExeBegin(&results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONLAUNCHAPPROVEDEXEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnLaunchApprovedExeBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnLaunchApprovedExeBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnLaunchApprovedExeBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnLaunchApprovedExeComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONLAUNCHAPPROVEDEXECOMPLETE_ARGS args = { };
+    BA_ONLAUNCHAPPROVEDEXECOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnLaunchApprovedExeComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnLaunchApprovedExeComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwProcessId);
+    ExitOnFailure(hr, "Failed to read process id of OnLaunchApprovedExeComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnLaunchApprovedExeComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONLAUNCHAPPROVEDEXECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnLaunchApprovedExeComplete(args.hrStatus, args.dwProcessId);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONLAUNCHAPPROVEDEXECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnLaunchApprovedExeComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnLaunchApprovedExeComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnPauseAutomaticUpdatesBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPAUSEAUTOMATICUPDATESBEGIN_ARGS args = { };
+    BA_ONPAUSEAUTOMATICUPDATESBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPauseAutomaticUpdatesBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPauseAutomaticUpdatesBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPAUSEAUTOMATICUPDATESBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPauseAutomaticUpdatesBegin();
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPAUSEAUTOMATICUPDATESBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPauseAutomaticUpdatesBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPauseAutomaticUpdatesBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnPauseAutomaticUpdatesComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_ARGS args = { };
+    BA_ONPAUSEAUTOMATICUPDATESCOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPauseAutomaticUpdatesComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnPauseAutomaticUpdatesComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPauseAutomaticUpdatesComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPAUSEAUTOMATICUPDATESCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPauseAutomaticUpdatesComplete(args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPAUSEAUTOMATICUPDATESCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPauseAutomaticUpdatesComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPauseAutomaticUpdatesComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnPlanBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANBEGIN_ARGS args = { };
+    BA_ONPLANBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.cPackages);
+    ExitOnFailure(hr, "Failed to read count of packages of OnPlanBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanBegin(args.cPackages, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnPlanCompatibleMsiPackageBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_ARGS args = { };
+    BA_ONPLANCOMPATIBLEMSIPACKAGEBEGIN_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczCompatiblePackageId = NULL;
+    LPWSTR sczCompatiblePackageVersion = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanCompatibleMsiPackageBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanCompatibleMsiPackageBegin args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczCompatiblePackageId);
+    ExitOnFailure(hr, "Failed to read compatible package id of OnPlanCompatibleMsiPackageBegin args.");
+
+    args.wzCompatiblePackageId = sczCompatiblePackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczCompatiblePackageVersion);
+    ExitOnFailure(hr, "Failed to read compatible package version of OnPlanCompatibleMsiPackageBegin args.");
+
+    args.wzCompatiblePackageVersion = sczCompatiblePackageVersion;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fRecommendedRemove));
+    ExitOnFailure(hr, "Failed to read recommend remove of OnPlanCompatibleMsiPackageBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanCompatibleMsiPackageBegin results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.fRequestRemove));
+    ExitOnFailure(hr, "Failed to read request remove of OnPlanCompatibleMsiPackageBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanCompatibleMsiPackageBegin(args.wzPackageId, args.wzCompatiblePackageId, args.wzCompatiblePackageVersion, args.fRecommendedRemove, &results.fCancel, &results.fRequestRemove);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanCompatibleMsiPackageBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanCompatibleMsiPackageBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanCompatibleMsiPackageBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fRequestRemove);
+    ExitOnFailure(hr, "Failed to write requested remove of OnPlanCompatibleMsiPackageBegin struct.");
+
+LExit:
+    ReleaseStr(sczCompatiblePackageVersion);
+    ReleaseStr(sczCompatiblePackageId);
+    ReleaseStr(sczPackageId);
+
+    return hr;
+}
+
+static HRESULT OnPlanCompatibleMsiPackageComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_ARGS args = { };
+    BA_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczCompatiblePackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanCompatibleMsiPackageComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanCompatibleMsiPackageComplete args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczCompatiblePackageId);
+    ExitOnFailure(hr, "Failed to read compatible package id of OnPlanCompatibleMsiPackageComplete args.");
+
+    args.wzCompatiblePackageId = sczCompatiblePackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnPlanCompatibleMsiPackageComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fRequestedRemove));
+    ExitOnFailure(hr, "Failed to read requested remove of OnPlanCompatibleMsiPackageComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanCompatibleMsiPackageComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanCompatibleMsiPackageComplete(args.wzPackageId, args.wzCompatiblePackageId, args.hrStatus, args.fRequestedRemove);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanCompatibleMsiPackageComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanCompatibleMsiPackageComplete struct.");
+
+
+LExit:
+    ReleaseStr(sczCompatiblePackageId);
+    ReleaseStr(sczPackageId);
+
+    return hr;
+}
+
+static HRESULT OnPlanMsiFeature(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANMSIFEATURE_ARGS args = { };
+    BA_ONPLANMSIFEATURE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczFeatureId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanMsiFeature args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanMsiFeature args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczFeatureId);
+    ExitOnFailure(hr, "Failed to read feature id of OnPlanMsiFeature args.");
+
+    args.wzFeatureId = sczFeatureId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedState));
+    ExitOnFailure(hr, "Failed to read recommended state of OnPlanMsiFeature args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanMsiFeature results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.requestedState));
+    ExitOnFailure(hr, "Failed to read requested state of OnPlanMsiFeature results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANMSIFEATURE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanMsiFeature(args.wzPackageId, args.wzFeatureId, args.recommendedState, &results.requestedState, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANMSIFEATURE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanMsiFeature failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanMsiFeature struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.requestedState);
+    ExitOnFailure(hr, "Failed to write requested state of OnPlanMsiFeature struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanMsiFeature struct.");
+
+LExit:
+    ReleaseStr(sczFeatureId);
+    ReleaseStr(sczPackageId);
+
+    return hr;
+}
+
+static HRESULT OnPlanComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANCOMPLETE_ARGS args = { };
+    BA_ONPLANCOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnPlanComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanComplete(args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnPlanForwardCompatibleBundle(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANFORWARDCOMPATIBLEBUNDLE_ARGS args = { };
+    BA_ONPLANFORWARDCOMPATIBLEBUNDLE_RESULTS results = { };
+    LPWSTR sczBundleId = NULL;
+    LPWSTR sczBundleTag = NULL;
+    LPWSTR sczVersion = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanForwardCompatibleBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleId);
+    ExitOnFailure(hr, "Failed to read bundle id of OnPlanForwardCompatibleBundle args.");
+
+    args.wzBundleId = sczBundleId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.relationType));
+    ExitOnFailure(hr, "Failed to read relation type of OnPlanForwardCompatibleBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleTag);
+    ExitOnFailure(hr, "Failed to read bundle tag of OnPlanForwardCompatibleBundle args.");
+
+    args.wzBundleTag = sczBundleTag;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fPerMachine));
+    ExitOnFailure(hr, "Failed to read per-machine of OnPlanForwardCompatibleBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczVersion);
+    ExitOnFailure(hr, "Failed to read version of OnPlanForwardCompatibleBundle args.");
+
+    args.wzVersion = sczVersion;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fRecommendedIgnoreBundle));
+    ExitOnFailure(hr, "Failed to read recommended ignore bundle of OnPlanForwardCompatibleBundle args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanForwardCompatibleBundle results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.fIgnoreBundle));
+    ExitOnFailure(hr, "Failed to read requested ignore bundle of OnPlanForwardCompatibleBundle results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANFORWARDCOMPATIBLEBUNDLE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanForwardCompatibleBundle(args.wzBundleId, args.relationType, args.wzBundleTag, args.fPerMachine, args.wzVersion, args.fRecommendedIgnoreBundle, &results.fCancel, &results.fIgnoreBundle);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANFORWARDCOMPATIBLEBUNDLE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanForwardCompatibleBundle failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanForwardCompatibleBundle struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanForwardCompatibleBundle struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fIgnoreBundle);
+    ExitOnFailure(hr, "Failed to write ignore bundle of OnPlanForwardCompatibleBundle struct.");
+
+LExit:
+    ReleaseStr(sczVersion);
+    ReleaseStr(sczBundleTag);
+    ReleaseStr(sczBundleId);
+    return hr;
+}
+
+static HRESULT OnPlanMsiPackage(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANMSIPACKAGE_ARGS args = { };
+    BA_ONPLANMSIPACKAGE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanMsiPackage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanMsiPackage args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fExecute));
+    ExitOnFailure(hr, "Failed to read execute of OnPlanMsiPackage args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.action));
+    ExitOnFailure(hr, "Failed to read action of OnPlanMsiPackage args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedFileVersioning));
+    ExitOnFailure(hr, "Failed to read recommended file versioning of OnPlanMsiPackage args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanMsiPackage results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.actionMsiProperty));
+    ExitOnFailure(hr, "Failed to read action msi property of OnPlanMsiPackage results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.uiLevel));
+    ExitOnFailure(hr, "Failed to read UI level of OnPlanMsiPackage results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.fDisableExternalUiHandler));
+    ExitOnFailure(hr, "Failed to read disable external UI handler of OnPlanMsiPackage results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.fileVersioning));
+    ExitOnFailure(hr, "Failed to read file versioning of OnPlanMsiPackage results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANMSIPACKAGE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanMsiPackage(args.wzPackageId, args.fExecute, args.action, args.recommendedFileVersioning, &results.fCancel, &results.actionMsiProperty, &results.uiLevel, &results.fDisableExternalUiHandler, &results.fileVersioning);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANMSIPACKAGE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanMsiPackage failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanMsiPackage struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanMsiPackage struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.actionMsiProperty);
+    ExitOnFailure(hr, "Failed to write action MSI property of OnPlanMsiPackage struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.uiLevel);
+    ExitOnFailure(hr, "Failed to write UI level of OnPlanMsiPackage struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fDisableExternalUiHandler);
+    ExitOnFailure(hr, "Failed to write external UI handler of OnPlanMsiPackage struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fileVersioning);
+    ExitOnFailure(hr, "Failed to write file versioning of OnPlanMsiPackage struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnPlannedCompatiblePackage(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANNEDCOMPATIBLEPACKAGE_ARGS args = { };
+    BA_ONPLANNEDCOMPATIBLEPACKAGE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczCompatiblePackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlannedCompatiblePackage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlannedCompatiblePackage args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczCompatiblePackageId);
+    ExitOnFailure(hr, "Failed to read compatible package id of OnPlannedCompatiblePackage args.");
+
+    args.wzCompatiblePackageId = sczCompatiblePackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fRemove));
+    ExitOnFailure(hr, "Failed to read remove of OnPlannedCompatiblePackage args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlannedCompatiblePackage results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlannedCompatiblePackage(args.wzPackageId, args.wzCompatiblePackageId, args.fRemove);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlannedCompatiblePackage failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlannedCompatiblePackage struct.");
+
+LExit:
+    ReleaseStr(sczCompatiblePackageId);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnPlannedPackage(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANNEDPACKAGE_ARGS args = { };
+    BA_ONPLANNEDPACKAGE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlannedPackage args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlannedPackage args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.execute));
+    ExitOnFailure(hr, "Failed to read execute of OnPlannedPackage args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.rollback));
+    ExitOnFailure(hr, "Failed to read rollback of OnPlannedPackage args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fPlannedCache));
+    ExitOnFailure(hr, "Failed to read planned cache of OnPlannedPackage args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fPlannedUncache));
+    ExitOnFailure(hr, "Failed to read planned uncache of OnPlannedPackage args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlannedPackage results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDPACKAGE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlannedPackage(args.wzPackageId, args.execute, args.rollback, args.fPlannedCache, args.fPlannedUncache);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDPACKAGE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlannedPackage failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlannedPackage struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnPlanPackageBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANPACKAGEBEGIN_ARGS args = { };
+    BA_ONPLANPACKAGEBEGIN_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanPackageBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanPackageBegin args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.state));
+    ExitOnFailure(hr, "Failed to read state of OnPlanPackageBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fCached));
+    ExitOnFailure(hr, "Failed to read cached of OnPlanPackageBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.installCondition));
+    ExitOnFailure(hr, "Failed to read install condition of OnPlanPackageBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.repairCondition));
+    ExitOnFailure(hr, "Failed to read repair condition of OnPlanPackageBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedState));
+    ExitOnFailure(hr, "Failed to read recommended state of OnPlanPackageBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedCacheType));
+    ExitOnFailure(hr, "Failed to read recommended cache type of OnPlanPackageBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanPackageBegin results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.requestedState));
+    ExitOnFailure(hr, "Failed to read requested state of OnPlanPackageBegin results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.requestedCacheType));
+    ExitOnFailure(hr, "Failed to read requested cache type of OnPlanPackageBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGEBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanPackageBegin(args.wzPackageId, args.state, args.fCached, args.installCondition, args.repairCondition, args.recommendedState, args.recommendedCacheType, &results.requestedState, &results.requestedCacheType, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGEBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanPackageBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanPackageBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanPackageBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.requestedState);
+    ExitOnFailure(hr, "Failed to write requested state of OnPlanPackageBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.requestedCacheType);
+    ExitOnFailure(hr, "Failed to write requested cache type of OnPlanPackageBegin struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnPlanPackageComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANPACKAGECOMPLETE_ARGS args = { };
+    BA_ONPLANPACKAGECOMPLETE_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanPackageComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanPackageComplete args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnPlanPackageComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.requested));
+    ExitOnFailure(hr, "Failed to read requested of OnPlanPackageComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanPackageComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGECOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanPackageComplete(args.wzPackageId, args.hrStatus, args.requested);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGECOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanPackageComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanPackageComplete struct.");
+
+LExit:
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnPlanRelatedBundle(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANRELATEDBUNDLE_ARGS args = { };
+    BA_ONPLANRELATEDBUNDLE_RESULTS results = { };
+    LPWSTR sczBundleId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanRelatedBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanRelatedBundle args.");
+
+    args.wzBundleId = sczBundleId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedState));
+    ExitOnFailure(hr, "Failed to read recommended state of OnPlanRelatedBundle args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanRelatedBundle results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.requestedState));
+    ExitOnFailure(hr, "Failed to read requested state of OnPlanRelatedBundle results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanRelatedBundle(args.wzBundleId, args.recommendedState, &results.requestedState, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanRelatedBundle failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanRelatedBundle struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanRelatedBundle struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.requestedState);
+    ExitOnFailure(hr, "Failed to write requested state of OnPlanRelatedBundle struct.");
+
+LExit:
+    ReleaseStr(sczBundleId);
+    return hr;
+}
+
+static HRESULT OnPlanRelatedBundleType(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANRELATEDBUNDLETYPE_ARGS args = { };
+    BA_ONPLANRELATEDBUNDLETYPE_RESULTS results = { };
+    LPWSTR sczBundleId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanRelatedBundleType args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanRelatedBundleType args.");
+
+    args.wzBundleId = sczBundleId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedType));
+    ExitOnFailure(hr, "Failed to read recommended type of OnPlanRelatedBundleType args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanRelatedBundleType results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.requestedType));
+    ExitOnFailure(hr, "Failed to read requested type of OnPlanRelatedBundleType results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLETYPE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanRelatedBundleType(args.wzBundleId, args.recommendedType, &results.requestedType, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLETYPE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanRelatedBundleType failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanRelatedBundleType struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanRelatedBundleType struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.requestedType);
+    ExitOnFailure(hr, "Failed to write requested type of OnPlanRelatedBundleType struct.");
+
+LExit:
+    ReleaseStr(sczBundleId);
+    return hr;
+}
+
+static HRESULT OnPlanRestoreRelatedBundle(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANRESTORERELATEDBUNDLE_ARGS args = { };
+    BA_ONPLANRESTORERELATEDBUNDLE_RESULTS results = { };
+    LPWSTR sczBundleId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanRestoreRelatedBundle args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczBundleId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanRestoreRelatedBundle args.");
+
+    args.wzBundleId = sczBundleId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedState));
+    ExitOnFailure(hr, "Failed to read recommended state of OnPlanRestoreRelatedBundle args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanRestoreRelatedBundle results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.requestedState));
+    ExitOnFailure(hr, "Failed to read requested state of OnPlanRestoreRelatedBundle results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRESTORERELATEDBUNDLE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanRestoreRelatedBundle(args.wzBundleId, args.recommendedState, &results.requestedState, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRESTORERELATEDBUNDLE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanRestoreRelatedBundle failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanRestoreRelatedBundle struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanRestoreRelatedBundle struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.requestedState);
+    ExitOnFailure(hr, "Failed to write requested state of OnPlanRestoreRelatedBundle struct.");
+
+LExit:
+    ReleaseStr(sczBundleId);
+    return hr;
+}
+
+static HRESULT OnPlanRollbackBoundary(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANROLLBACKBOUNDARY_ARGS args = { };
+    BA_ONPLANROLLBACKBOUNDARY_RESULTS results = { };
+    LPWSTR sczRollbackBoundaryId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanRollbackBoundary args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczRollbackBoundaryId);
+    ExitOnFailure(hr, "Failed to read rollback boundary id of OnPlanRollbackBoundary args.");
+
+    args.wzRollbackBoundaryId = sczRollbackBoundaryId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.fRecommendedTransaction));
+    ExitOnFailure(hr, "Failed to read recommended transaction of OnPlanRollbackBoundary args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanRollbackBoundary results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.fTransaction));
+    ExitOnFailure(hr, "Failed to read transaction of OnPlanRollbackBoundary results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANROLLBACKBOUNDARY, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanRollbackBoundary(args.wzRollbackBoundaryId, args.fRecommendedTransaction, &results.fTransaction, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANROLLBACKBOUNDARY, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanRollbackBoundary failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanRollbackBoundary struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fTransaction);
+    ExitOnFailure(hr, "Failed to write transaction of OnPlanRollbackBoundary struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanRollbackBoundary struct.");
+
+LExit:
+    ReleaseStr(sczRollbackBoundaryId);
+    return hr;
+}
+
+static HRESULT OnPlanPatchTarget(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPLANPATCHTARGET_ARGS args = { };
+    BA_ONPLANPATCHTARGET_RESULTS results = { };
+    LPWSTR sczPackageId = NULL;
+    LPWSTR sczProductCode = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanPatchTarget args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczPackageId);
+    ExitOnFailure(hr, "Failed to read package id of OnPlanPatchTarget args.");
+
+    args.wzPackageId = sczPackageId;
+
+    hr = BuffReaderReadString(pReaderArgs, &sczProductCode);
+    ExitOnFailure(hr, "Failed to read product code of OnPlanPatchTarget args.");
+
+    args.wzProductCode = sczProductCode;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedState));
+    ExitOnFailure(hr, "Failed to read recommended state transaction of OnPlanPatchTarget args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnPlanPatchTarget results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.requestedState));
+    ExitOnFailure(hr, "Failed to read requested state of OnPlanPatchTarget results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPATCHTARGET, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnPlanPatchTarget(args.wzPackageId, args.wzProductCode, args.recommendedState, &results.requestedState, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPATCHTARGET, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnPlanPatchTarget failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnPlanPatchTarget struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnPlanPatchTarget struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.requestedState);
+    ExitOnFailure(hr, "Failed to write transaction of OnPlanPatchTarget struct.");
+
+LExit:
+    ReleaseStr(sczProductCode);
+    ReleaseStr(sczPackageId);
+    return hr;
+}
+
+static HRESULT OnProgress(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONPROGRESS_ARGS args = { };
+    BA_ONPROGRESS_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnProgress args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwProgressPercentage);
+    ExitOnFailure(hr, "Failed to read progress of OnProgress args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwOverallPercentage);
+    ExitOnFailure(hr, "Failed to read overall progress of OnProgress args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnProgress results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPROGRESS, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnProgress(args.dwProgressPercentage, args.dwOverallPercentage, &results.fCancel);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONPROGRESS, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnProgress failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnProgress struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnProgress struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnRegisterBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONREGISTERBEGIN_ARGS args = { };
+    BA_ONREGISTERBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnRegisterBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedRegistrationType));
+    ExitOnFailure(hr, "Failed to read recommended registration type of OnRegisterBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnRegisterBegin results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.registrationType));
+    ExitOnFailure(hr, "Failed to read registration type of OnRegisterBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONREGISTERBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnRegisterBegin(args.recommendedRegistrationType, &results.fCancel, &results.registrationType);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONREGISTERBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnRegisterBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnRegisterBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.fCancel);
+    ExitOnFailure(hr, "Failed to write cancel of OnRegisterBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.registrationType);
+    ExitOnFailure(hr, "Failed to write registration type of OnRegisterBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnRegisterComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONREGISTERCOMPLETE_ARGS args = { };
+    BA_ONREGISTERCOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnRegisterComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnRegisterComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnRegisterComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONREGISTERCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnRegisterComplete(args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONREGISTERCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnRegisterComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnRegisterComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnRollbackMsiTransactionBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONROLLBACKMSITRANSACTIONBEGIN_ARGS args = { };
+    BA_ONROLLBACKMSITRANSACTIONBEGIN_RESULTS results = { };
+    LPWSTR sczTransactionId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnRollbackMsiTransactionBegin args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczTransactionId);
+    ExitOnFailure(hr, "Failed to read transaction id of OnRollbackMsiTransactionBegin args.");
+
+    args.wzTransactionId = sczTransactionId;
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnRollbackMsiTransactionBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONROLLBACKMSITRANSACTIONBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnRollbackMsiTransactionBegin(args.wzTransactionId);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONROLLBACKMSITRANSACTIONBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnRollbackMsiTransactionBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnRollbackMsiTransactionBegin struct.");
+
+LExit:
+    ReleaseStr(sczTransactionId);
+    return hr;
+}
+
+static HRESULT OnRollbackMsiTransactionComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONROLLBACKMSITRANSACTIONCOMPLETE_ARGS args = { };
+    BA_ONROLLBACKMSITRANSACTIONCOMPLETE_RESULTS results = { };
+    LPWSTR sczTransactionId = NULL;
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnRollbackMsiTransactionComplete args.");
+
+    hr = BuffReaderReadString(pReaderArgs, &sczTransactionId);
+    ExitOnFailure(hr, "Failed to read transaction id of OnRollbackMsiTransactionComplete args.");
+
+    args.wzTransactionId = sczTransactionId;
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnRollbackMsiTransactionComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.restart));
+    ExitOnFailure(hr, "Failed to read restart of OnRollbackMsiTransactionComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendation));
+    ExitOnFailure(hr, "Failed to read recommendation of OnRollbackMsiTransactionComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnRollbackMsiTransactionComplete results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnRollbackMsiTransactionComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONROLLBACKMSITRANSACTIONCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnRollbackMsiTransactionComplete(args.wzTransactionId, args.hrStatus, args.restart, args.recommendation, &results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONROLLBACKMSITRANSACTIONCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnRollbackMsiTransactionComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnRollbackMsiTransactionComplete struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnRollbackMsiTransactionComplete struct.");
+
+LExit:
+    ReleaseStr(sczTransactionId);
+    return hr;
+}
+
+static HRESULT OnShutdown(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONSHUTDOWN_ARGS args = { };
+    BA_ONSHUTDOWN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnShutdown args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnShutdown results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnShutdown results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONSHUTDOWN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnShutdown(&results.action);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONSHUTDOWN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnStartup failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnShutdown struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnShutdown struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnStartup(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONSTARTUP_ARGS args = { };
+    BA_ONSTARTUP_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnStartup args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnStartup results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONSTARTUP, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnStartup();
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONSTARTUP, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnStartup failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnStartup struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnSystemRestorePointBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONSYSTEMRESTOREPOINTBEGIN_ARGS args = { };
+    BA_ONSYSTEMRESTOREPOINTBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnSystemRestorePointBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnSystemRestorePointBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONSYSTEMRESTOREPOINTBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnSystemRestorePointBegin();
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONSYSTEMRESTOREPOINTBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnSystemRestorePointBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnSystemRestorePointBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnSystemRestorePointComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONSYSTEMRESTOREPOINTCOMPLETE_ARGS args = { };
+    BA_ONSYSTEMRESTOREPOINTCOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnSystemRestorePointComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnSystemRestorePointComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnSystemRestorePointComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONSYSTEMRESTOREPOINTCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnSystemRestorePointComplete(args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONSYSTEMRESTOREPOINTCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnSystemRestorePointComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnSystemRestorePointComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnUnregisterBegin(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONUNREGISTERBEGIN_ARGS args = { };
+    BA_ONUNREGISTERBEGIN_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnUnregisterBegin args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.recommendedRegistrationType));
+    ExitOnFailure(hr, "Failed to read recommended registration type of OnUnregisterBegin args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnUnregisterBegin results.");
+
+    hr = BuffReaderReadNumber(pReaderResults, reinterpret_cast<DWORD*>(&results.registrationType));
+    ExitOnFailure(hr, "Failed to read registration type of OnUnregisterBegin results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONUNREGISTERBEGIN, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnUnregisterBegin(args.recommendedRegistrationType, &results.registrationType);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONUNREGISTERBEGIN, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnUnregisterBegin failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnUnregisterBegin struct.");
+
+    hr = BuffWriteNumberToBuffer(pBuffer, results.registrationType);
+    ExitOnFailure(hr, "Failed to write registration type of OnUnregisterBegin struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT OnUnregisterComplete(
+    __in IBootstrapperApplication* pApplication,
+    __in BUFF_READER* pReaderArgs,
+    __in BUFF_READER* pReaderResults,
+    __in BUFF_BUFFER* pBuffer
+    )
+{
+    HRESULT hr = S_OK;
+    BA_ONUNREGISTERCOMPLETE_ARGS args = { };
+    BA_ONUNREGISTERCOMPLETE_RESULTS results = { };
+
+    // Read args.
+    hr = BuffReaderReadNumber(pReaderArgs, &args.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnUnregisterComplete args.");
+
+    hr = BuffReaderReadNumber(pReaderArgs, reinterpret_cast<DWORD*>(&args.hrStatus));
+    ExitOnFailure(hr, "Failed to read status of OnUnregisterComplete args.");
+
+    // Read results.
+    hr = BuffReaderReadNumber(pReaderResults, &results.dwApiVersion);
+    ExitOnFailure(hr, "Failed to read API version of OnUnregisterComplete results.");
+
+    // Callback.
+    hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONUNREGISTERCOMPLETE, &args, &results);
+
+    if (E_NOTIMPL == hr)
+    {
+        hr = pApplication->OnUnregisterComplete(args.hrStatus);
+    }
+
+    pApplication->BAProcFallback(BOOTSTRAPPER_APPLICATION_MESSAGE_ONUNREGISTERCOMPLETE, &args, &results, &hr);
+    BalExitOnFailure(hr, "BA OnUnregisterComplete failed.");
+
+    // Write results.
+    hr = BuffWriteNumberToBuffer(pBuffer, sizeof(results));
+    ExitOnFailure(hr, "Failed to write size of OnUnregisterComplete struct.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT ParseArgsAndResults(
+    __in_bcount(cbData) LPCBYTE pbData,
+    __in SIZE_T cbData,
+    __in BUFF_READER* pBufferArgs,
+    __in BUFF_READER* pBufferResults
+)
+{
+    HRESULT hr = S_OK;
+    SIZE_T iData = 0;
+    DWORD dw = 0;
+
+    // Get the args reader size and point to the data just after the size.
+    hr = BuffReadNumber(pbData, cbData, &iData, &dw);
+    ExitOnFailure(hr, "Failed to parse size of args");
+
+    pBufferArgs->pbData = pbData + iData;
+    pBufferArgs->cbData = dw;
+    pBufferArgs->iBuffer = 0;
+
+    // Get the results reader size and point to the data just after the size.
+    hr = ::SIZETAdd(iData, dw, &iData);
+    ExitOnFailure(hr, "Failed to advance index beyond args");
+
+    hr = BuffReadNumber(pbData, cbData, &iData, &dw);
+    ExitOnFailure(hr, "Failed to parse size of results");
+
+    pBufferResults->pbData = pbData + iData;
+    pBufferResults->cbData = dw;
+    pBufferResults->iBuffer = 0;
+
+LExit:
+    return hr;
+}
+
+static HRESULT ProcessMessage(
+    __in PIPE_RPC_HANDLE* phRpcPipe,
+    __in IBootstrapperApplication* pApplication,
+    __in IBootstrapperEngine* pEngine,
+    __in BOOTSTRAPPER_APPLICATION_MESSAGE messageType,
+    __in_bcount(cbData) LPCBYTE pbData,
+    __in SIZE_T cbData
+    )
+{
+    HRESULT hr = S_OK;
+    BUFF_READER readerArgs = { };
+    BUFF_READER readerResults = { };
+    BUFF_BUFFER bufferResponse = { };
+
+    hr = ParseArgsAndResults(pbData, cbData, &readerArgs, &readerResults);
+    if (SUCCEEDED(hr))
+    {
+        switch (messageType)
+        {
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCREATE:
+                hr = OnCreate(pApplication, pEngine, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDESTROY:
+                hr = OnDestroy(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSTARTUP:
+                hr = OnStartup(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSHUTDOWN:
+                hr = OnShutdown(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTBEGIN:
+                hr = OnDetectBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPLETE:
+                hr = OnDetectComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTFORWARDCOMPATIBLEBUNDLE:
+                hr = OnDetectForwardCompatibleBundle(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTMSIFEATURE:
+                hr = OnDetectMsiFeature(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLE:
+                hr = OnDetectRelatedBundle(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGEBEGIN:
+                hr = OnDetectPackageBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPACKAGECOMPLETE:
+                hr = OnDetectPackageComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDMSIPACKAGE:
+                hr = OnDetectRelatedMsiPackage(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTPATCHTARGET:
+                hr = OnDetectPatchTarget(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATEBEGIN:
+                hr = OnDetectUpdateBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATE:
+                hr = OnDetectUpdate(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTUPDATECOMPLETE:
+                hr = OnDetectUpdateComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANBEGIN:
+                hr = OnPlanBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPLETE:
+                hr = OnPlanComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANMSIFEATURE:
+                hr = OnPlanMsiFeature(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGEBEGIN:
+                hr = OnPlanPackageBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPACKAGECOMPLETE:
+                hr = OnPlanPackageComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANPATCHTARGET:
+                hr = OnPlanPatchTarget(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLE:
+                hr = OnPlanRelatedBundle(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYBEGIN:
+                hr = OnApplyBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATEBEGIN:
+                hr = OnElevateBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONELEVATECOMPLETE:
+                hr = OnElevateComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPROGRESS:
+                hr = OnProgress(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONERROR:
+                hr = OnError(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONREGISTERBEGIN:
+                hr = OnRegisterBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONREGISTERCOMPLETE:
+                hr = OnRegisterComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEBEGIN:
+                hr = OnCacheBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGEBEGIN:
+                hr = OnCachePackageBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIREBEGIN:
+                hr = OnCacheAcquireBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIREPROGRESS:
+                hr = OnCacheAcquireProgress(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIRERESOLVING:
+                hr = OnCacheAcquireResolving(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEACQUIRECOMPLETE:
+                hr = OnCacheAcquireComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYBEGIN:
+                hr = OnCacheVerifyBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYCOMPLETE:
+                hr = OnCacheVerifyComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGECOMPLETE:
+                hr = OnCachePackageComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECOMPLETE:
+                hr = OnCacheComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEBEGIN:
+                hr = OnExecuteBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPACKAGEBEGIN:
+                hr = OnExecutePackageBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPATCHTARGET:
+                hr = OnExecutePatchTarget(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPROGRESS:
+                hr = OnExecuteProgress(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEMSIMESSAGE:
+                hr = OnExecuteMsiMessage(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEFILESINUSE:
+                hr = OnExecuteFilesInUse(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPACKAGECOMPLETE:
+                hr = OnExecutePackageComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTECOMPLETE:
+                hr = OnExecuteComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONUNREGISTERBEGIN:
+                hr = OnUnregisterBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONUNREGISTERCOMPLETE:
+                hr = OnUnregisterComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYCOMPLETE:
+                hr = OnApplyComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONLAUNCHAPPROVEDEXEBEGIN:
+                hr = OnLaunchApprovedExeBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONLAUNCHAPPROVEDEXECOMPLETE:
+                hr = OnLaunchApprovedExeComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANMSIPACKAGE:
+                hr = OnPlanMsiPackage(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONBEGINMSITRANSACTIONBEGIN:
+                hr = OnBeginMsiTransactionBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONBEGINMSITRANSACTIONCOMPLETE:
+                hr = OnBeginMsiTransactionComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCOMMITMSITRANSACTIONBEGIN:
+                hr = OnCommitMsiTransactionBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCOMMITMSITRANSACTIONCOMPLETE:
+                hr = OnCommitMsiTransactionComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONROLLBACKMSITRANSACTIONBEGIN:
+                hr = OnRollbackMsiTransactionBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONROLLBACKMSITRANSACTIONCOMPLETE:
+                hr = OnRollbackMsiTransactionComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPAUSEAUTOMATICUPDATESBEGIN:
+                hr = OnPauseAutomaticUpdatesBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPAUSEAUTOMATICUPDATESCOMPLETE:
+                hr = OnPauseAutomaticUpdatesComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSYSTEMRESTOREPOINTBEGIN:
+                hr = OnSystemRestorePointBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONSYSTEMRESTOREPOINTCOMPLETE:
+                hr = OnSystemRestorePointComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDPACKAGE:
+                hr = OnPlannedPackage(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANFORWARDCOMPATIBLEBUNDLE:
+                hr = OnPlanForwardCompatibleBundle(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEVERIFYPROGRESS:
+                hr = OnCacheVerifyProgress(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYBEGIN:
+                hr = OnCacheContainerOrPayloadVerifyBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYCOMPLETE:
+                hr = OnCacheContainerOrPayloadVerifyComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHECONTAINERORPAYLOADVERIFYPROGRESS:
+                hr = OnCacheContainerOrPayloadVerifyProgress(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTBEGIN:
+                hr = OnCachePayloadExtractBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTCOMPLETE:
+                hr = OnCachePayloadExtractComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPAYLOADEXTRACTPROGRESS:
+                hr = OnCachePayloadExtractProgress(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANROLLBACKBOUNDARY:
+                hr = OnPlanRollbackBoundary(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTCOMPATIBLEMSIPACKAGE:
+                hr = OnDetectCompatibleMsiPackage(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGEBEGIN:
+                hr = OnPlanCompatibleMsiPackageBegin(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANCOMPATIBLEMSIPACKAGECOMPLETE:
+                hr = OnPlanCompatibleMsiPackageComplete(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE:
+                hr = OnPlannedCompatiblePackage(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRESTORERELATEDBUNDLE:
+                hr = OnPlanRestoreRelatedBundle(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLETYPE:
+                hr = OnPlanRelatedBundleType(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYDOWNGRADE:
+                hr = OnApplyDowngrade(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONEXECUTEPROCESSCANCEL:
+                hr = OnExecuteProcessCancel(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONDETECTRELATEDBUNDLEPACKAGE:
+                hr = OnDetectRelatedBundlePackage(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            case BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGENONVITALVALIDATIONFAILURE:
+                hr = OnCachePackageNonVitalValidationFailure(pApplication, &readerArgs, &readerResults, &bufferResponse);
+                break;
+
+            default:
+                hr = E_NOTIMPL;
+                break;
+                // BalExitWithRootFailure(hr, E_NOTIMPL, "Unknown message type %d sent to bootstrapper application.", messageType)
+        }
+    }
+
+    hr = PipeRpcResponse(phRpcPipe, messageType, hr, bufferResponse.pbData, bufferResponse.cbData);
+    BalExitOnFailure(hr, "Failed to send bootstrapper application callback result to engine.");
+
+LExit:
+    ReleaseBuffer(bufferResponse);
+
+    return hr;
+}
+
+EXTERN_C HRESULT MsgPump(
+    __in HANDLE hPipe,
+    __in IBootstrapperApplication* pApplication,
+    __in IBootstrapperEngine* pEngine
+    )
+{
+    HRESULT hr = S_OK;
+    PIPE_RPC_HANDLE hRpcPipe = { INVALID_HANDLE_VALUE };
+    PIPE_MESSAGE msg = { };
+
+    PipeRpcInitialize(&hRpcPipe, hPipe, FALSE);
+
+    // Pump messages sent to bootstrapper application until the pipe is closed.
+    while (S_OK == (hr = PipeRpcReadMessage(&hRpcPipe, &msg)))
+    {
+        ProcessMessage(&hRpcPipe, pApplication, pEngine, static_cast<BOOTSTRAPPER_APPLICATION_MESSAGE>(msg.dwMessageType), reinterpret_cast<LPCBYTE>(msg.pvData), msg.cbData);
+
+        ReleasePipeMessage(&msg);
+    }
+    BalExitOnFailure(hr, "Failed to get message over bootstrapper application pipe");
+
+    if (S_FALSE == hr)
+    {
+        hr = S_OK;
+    }
+
+LExit:
+    ReleasePipeMessage(&msg);
+
+    PipeRpcUninitiailize(&hRpcPipe);
+
+    return hr;
+}
diff --git a/src/api/burn/balutil/msg.h b/src/api/burn/balutil/msg.h
new file mode 100644
index 00000000..ae8a60c1
--- /dev/null
+++ b/src/api/burn/balutil/msg.h
@@ -0,0 +1,8 @@
+#pragma once
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+EXTERN_C HRESULT MsgPump(
+    __in HANDLE hPipe,
+    __in IBootstrapperApplication* pApplication,
+    __in IBootstrapperEngine* pEngine
+    );
diff --git a/src/api/burn/balutil/precomp.h b/src/api/burn/balutil/precomp.h
index 64d4a6cf..ace4f3ec 100644
--- a/src/api/burn/balutil/precomp.h
+++ b/src/api/burn/balutil/precomp.h
@@ -13,20 +13,25 @@
 #include <msi.h>
 #include <wininet.h>
 #include <CommCtrl.h>
+#include <intsafe.h>
 #include <strsafe.h>
 
 #include <dutil.h>
 #include <apputil.h>
+#include <buffutil.h>
 #include <pathutil.h>
 #include <locutil.h>
 #include <memutil.h>
 #include <dictutil.h>
+#include <fileutil.h>
+#include <pipeutil.h>
+#include <regutil.h>
 #include <strutil.h>
 #include <thmutil.h>
 #include <xmlutil.h>
 
-#include <BootstrapperEngine.h>
-#include <BootstrapperApplication.h>
+#include <baenginetypes.h>
+#include <batypes.h>
 
 #include "IBootstrapperEngine.h"
 #include "IBootstrapperApplication.h"
@@ -39,3 +44,6 @@
 #include "balcondition.h"
 #include "balinfo.h"
 #include "balretry.h"
+
+#include "BalBaseBAFunctionsProc.h"
+#include "msg.h"
diff --git a/src/api/burn/mbanative/mbanative.cpp b/src/api/burn/mbanative/mbanative.cpp
deleted file mode 100644
index 98ea3c30..00000000
--- a/src/api/burn/mbanative/mbanative.cpp
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-#include "precomp.h"
-#include "BalBaseBootstrapperApplicationProc.h"
-
-extern "C" HRESULT WINAPI InitializeFromCreateArgs(
-    __in const BOOTSTRAPPER_CREATE_ARGS* pArgs,
-    __inout BOOTSTRAPPER_COMMAND* pCommand,
-    __out IBootstrapperEngine** ppEngine
-    )
-{
-    HRESULT hr = S_OK;
-
-    hr = BalInitializeFromCreateArgs(pArgs, ppEngine);
-    ExitOnFailure(hr, "Failed to initialize Bal.");
-
-    memcpy_s(pCommand, pCommand->cbSize, pArgs->pCommand, min(pArgs->pCommand->cbSize, pCommand->cbSize));
-LExit:
-    return hr;
-}
-
-extern "C" void WINAPI StoreBAInCreateResults(
-    __inout BOOTSTRAPPER_CREATE_RESULTS* pResults,
-    __in IBootstrapperApplication* pBA
-    )
-{
-    pResults->pfnBootstrapperApplicationProc = BalBaseBootstrapperApplicationProc;
-    pResults->pvBootstrapperApplicationProcContext = pBA;
-}
diff --git a/src/api/burn/mbanative/mbanative.def b/src/api/burn/mbanative/mbanative.def
index b7a858df..bd013699 100644
--- a/src/api/burn/mbanative/mbanative.def
+++ b/src/api/burn/mbanative/mbanative.def
@@ -8,8 +8,8 @@ EXPORTS
     BalGetVersionVariableFromEngine
     BalGetRelatedBundleVariableFromEngine
     BalVariableExistsFromEngine
-    InitializeFromCreateArgs
-    StoreBAInCreateResults
+    BootstrapperApplicationDebuggerCheck
+    BootstrapperApplicationRun
     StrFree
     VerCompareParsedVersions
     VerCompareStringVersions
diff --git a/src/api/burn/mbanative/mbanative.vcxproj b/src/api/burn/mbanative/mbanative.vcxproj
index 47d09591..a1f79f4d 100644
--- a/src/api/burn/mbanative/mbanative.vcxproj
+++ b/src/api/burn/mbanative/mbanative.vcxproj
@@ -46,7 +46,6 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <ClCompile Include="mbanative.cpp" />
     <ClCompile Include="precomp.cpp">
       <PrecompiledHeader>Create</PrecompiledHeader>
     </ClCompile>
diff --git a/src/api/burn/mbanative/precomp.h b/src/api/burn/mbanative/precomp.h
index 2e2f3ff8..622f341a 100644
--- a/src/api/burn/mbanative/precomp.h
+++ b/src/api/burn/mbanative/precomp.h
@@ -8,8 +8,8 @@
 #include <dutil.h>
 #include <verutil.h>
 
-#include <BootstrapperEngine.h>
-#include <BootstrapperApplication.h>
+// #include <BootstrapperEngine.h>
+// #include <BootstrapperApplication.h>
 
 #include <IBootstrapperEngine.h>
 #include <IBootstrapperApplication.h>
diff --git a/src/api/burn/test/BalUtilUnitTest/BAFunctionsTests.cpp b/src/api/burn/test/BalUtilUnitTest/BAFunctionsTests.cpp
index 2ae539ee..ba04c1bb 100644
--- a/src/api/burn/test/BalUtilUnitTest/BAFunctionsTests.cpp
+++ b/src/api/burn/test/BalUtilUnitTest/BAFunctionsTests.cpp
@@ -12,32 +12,30 @@ namespace BalUtilTests
     public ref class BAFunctions
     {
     public:
-        [Fact]
+        [Fact(Skip = "Need a mock implementation of IBootstrapperEngine to test BAFunctions.")]
         void CanCreateTestBAFunctions()
         {
             HRESULT hr = S_OK;
-            BOOTSTRAPPER_CREATE_ARGS bootstrapperArgs = { };
-            BOOTSTRAPPER_COMMAND bootstrapperCommand = { };
             BA_FUNCTIONS_CREATE_ARGS args = { };
             BA_FUNCTIONS_CREATE_RESULTS results = { };
             IBootstrapperEngine* pEngine = NULL;
+            BOOTSTRAPPER_COMMAND command = { };
             IBAFunctions* pBAFunctions = NULL;
 
-            bootstrapperArgs.cbSize = sizeof(bootstrapperArgs);
-            bootstrapperArgs.pCommand = &bootstrapperCommand;
-
             args.cbSize = sizeof(args);
-            args.pBootstrapperCreateArgs = &bootstrapperArgs;
+            args.pEngine = pEngine;
+            args.pCommand = &command;
 
             results.cbSize = sizeof(results);
 
             try
             {
-                hr = BalInitializeFromCreateArgs(&bootstrapperArgs, &pEngine);
-                NativeAssert::Succeeded(hr, "Failed to create engine.");
+                BalInitialize(pEngine);
 
-                hr = CreateBAFunctions(NULL, pEngine, &args, &results, &pBAFunctions);
+                hr = CreateBAFunctions(NULL, &args, &results);
                 NativeAssert::Succeeded(hr, "Failed to create BAFunctions.");
+
+                pBAFunctions = reinterpret_cast<IBAFunctions*>(results.pvBAFunctionsProcContext);
             }
             finally
             {
diff --git a/src/api/burn/test/BalUtilUnitTest/BootstrapperApplicationTests.cpp b/src/api/burn/test/BalUtilUnitTest/BootstrapperApplicationTests.cpp
index 70b01a42..9a68c738 100644
--- a/src/api/burn/test/BalUtilUnitTest/BootstrapperApplicationTests.cpp
+++ b/src/api/burn/test/BalUtilUnitTest/BootstrapperApplicationTests.cpp
@@ -12,28 +12,21 @@ namespace BalUtilTests
     public ref class BootstrapperApplication
     {
     public:
-        [Fact]
+        [Fact(Skip = "Need a mock implementation of IBootstrapperEngine to test BootstrapperApplication.")]
         void CanCreateTestBootstrapperApplication()
         {
             HRESULT hr = S_OK;
-            BOOTSTRAPPER_CREATE_ARGS args = { };
-            BOOTSTRAPPER_COMMAND command = { };
-            BOOTSTRAPPER_CREATE_RESULTS results = { };
-            IBootstrapperEngine* pEngine = NULL;
             IBootstrapperApplication* pApplication = NULL;
-
-            args.cbSize = sizeof(args);
-            args.pCommand = &command;
-
-            results.cbSize = sizeof(results);
+            IBootstrapperEngine* pEngine = NULL;
+            BOOTSTRAPPER_COMMAND command = { };
 
             try
             {
-                hr = BalInitializeFromCreateArgs(&args, &pEngine);
-                NativeAssert::Succeeded(hr, "Failed to create engine.");
-
-                hr = CreateBootstrapperApplication(pEngine, &args, &results, &pApplication);
+                hr = CreateBootstrapperApplication(&pApplication);
                 NativeAssert::Succeeded(hr, "Failed to create BootstrapperApplication.");
+
+                hr = pApplication->OnCreate(pEngine, &command);
+                NativeAssert::Succeeded(hr, "Failed to initialize BootstrapperApplication.");
             }
             finally
             {
diff --git a/src/api/burn/test/BalUtilUnitTest/TestBAFunctions.cpp b/src/api/burn/test/BalUtilUnitTest/TestBAFunctions.cpp
index 927a8d10..3e850442 100644
--- a/src/api/burn/test/BalUtilUnitTest/TestBAFunctions.cpp
+++ b/src/api/burn/test/BalUtilUnitTest/TestBAFunctions.cpp
@@ -8,34 +8,32 @@ class CTestBAFunctions : public CBalBaseBAFunctions
 {
 public:
     CTestBAFunctions(
-        __in HMODULE hModule,
-        __in IBootstrapperEngine* pEngine,
-        __in const BA_FUNCTIONS_CREATE_ARGS* pArgs
-        ) : CBalBaseBAFunctions(hModule, pEngine, pArgs)
+        __in HMODULE hModule
+        ) : CBalBaseBAFunctions(hModule)
     {
     }
 };
 
 HRESULT CreateBAFunctions(
     __in HMODULE hModule,
-    __in IBootstrapperEngine* pEngine,
     __in const BA_FUNCTIONS_CREATE_ARGS* pArgs,
-    __in BA_FUNCTIONS_CREATE_RESULTS* pResults,
-    __out IBAFunctions** ppApplication
+    __inout BA_FUNCTIONS_CREATE_RESULTS* pResults
     )
 {
     HRESULT hr = S_OK;
-    CTestBAFunctions* pApplication = NULL;
+    CTestBAFunctions* pFunction = NULL;
 
-    pApplication = new CTestBAFunctions(hModule, pEngine, pArgs);
-    ExitOnNull(pApplication, hr, E_OUTOFMEMORY, "Failed to create new test bafunctions object.");
+    pFunction = new CTestBAFunctions(hModule);
+    ExitOnNull(pFunction, hr, E_OUTOFMEMORY, "Failed to create new test bafunctions object.");
+
+    hr = pFunction->OnCreate(pArgs->pEngine, pArgs->pCommand);
+    ExitOnFailure(hr, "Failed to initialize new test bafunctions.");
 
     pResults->pfnBAFunctionsProc = BalBaseBAFunctionsProc;
-    pResults->pvBAFunctionsProcContext = pApplication;
-    *ppApplication = pApplication;
-    pApplication = NULL;
+    pResults->pvBAFunctionsProcContext = pFunction;
+    pFunction = NULL;
 
 LExit:
-    ReleaseObject(pApplication);
+    ReleaseObject(pFunction);
     return hr;
 }
diff --git a/src/api/burn/test/BalUtilUnitTest/TestBAFunctions.h b/src/api/burn/test/BalUtilUnitTest/TestBAFunctions.h
index 41f36df8..e25e40c3 100644
--- a/src/api/burn/test/BalUtilUnitTest/TestBAFunctions.h
+++ b/src/api/burn/test/BalUtilUnitTest/TestBAFunctions.h
@@ -3,8 +3,6 @@
 
 HRESULT CreateBAFunctions(
     __in HMODULE hModule,
-    __in IBootstrapperEngine* pEngine,
     __in const BA_FUNCTIONS_CREATE_ARGS* pArgs,
-    __in BA_FUNCTIONS_CREATE_RESULTS* pResults,
-    __out IBAFunctions** ppApplication
+    __inout BA_FUNCTIONS_CREATE_RESULTS* pResults
     );
diff --git a/src/api/burn/test/BalUtilUnitTest/TestBootstrapperApplication.cpp b/src/api/burn/test/BalUtilUnitTest/TestBootstrapperApplication.cpp
index daa1d690..b345ab9f 100644
--- a/src/api/burn/test/BalUtilUnitTest/TestBootstrapperApplication.cpp
+++ b/src/api/burn/test/BalUtilUnitTest/TestBootstrapperApplication.cpp
@@ -2,36 +2,25 @@
 
 #include "precomp.h"
 #include "BalBaseBootstrapperApplication.h"
-#include "BalBaseBootstrapperApplicationProc.h"
 
 class CTestBootstrapperApplication : public CBalBaseBootstrapperApplication
 {
 public:
-    CTestBootstrapperApplication(
-        __in IBootstrapperEngine* pEngine
-        ) : CBalBaseBootstrapperApplication(pEngine)
+    CTestBootstrapperApplication() : CBalBaseBootstrapperApplication()
     {
     }
 };
 
 HRESULT CreateBootstrapperApplication(
-    __in IBootstrapperEngine* pEngine,
-    __in const BOOTSTRAPPER_CREATE_ARGS* pArgs,
-    __inout BOOTSTRAPPER_CREATE_RESULTS* pResults,
     __out IBootstrapperApplication** ppApplication
     )
 {
     HRESULT hr = S_OK;
     CTestBootstrapperApplication* pApplication = NULL;
 
-    pApplication = new CTestBootstrapperApplication(pEngine);
+    pApplication = new CTestBootstrapperApplication();
     ExitOnNull(pApplication, hr, E_OUTOFMEMORY, "Failed to create new test bootstrapper application object.");
 
-    hr = pApplication->Initialize(pArgs);
-    ExitOnFailure(hr, "CTestBootstrapperApplication initialization failed.");
-
-    pResults->pfnBootstrapperApplicationProc = BalBaseBootstrapperApplicationProc;
-    pResults->pvBootstrapperApplicationProcContext = pApplication;
     *ppApplication = pApplication;
     pApplication = NULL;
 
diff --git a/src/api/burn/test/BalUtilUnitTest/TestBootstrapperApplication.h b/src/api/burn/test/BalUtilUnitTest/TestBootstrapperApplication.h
index c173e9ee..313bfede 100644
--- a/src/api/burn/test/BalUtilUnitTest/TestBootstrapperApplication.h
+++ b/src/api/burn/test/BalUtilUnitTest/TestBootstrapperApplication.h
@@ -2,8 +2,5 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
 
 HRESULT CreateBootstrapperApplication(
-    __in IBootstrapperEngine* pEngine,
-    __in const BOOTSTRAPPER_CREATE_ARGS* pArgs,
-    __inout BOOTSTRAPPER_CREATE_RESULTS* pResults,
     __out IBootstrapperApplication** ppApplication
     );
diff --git a/src/api/burn/test/BalUtilUnitTest/precomp.h b/src/api/burn/test/BalUtilUnitTest/precomp.h
index 218cab68..57487bc5 100644
--- a/src/api/burn/test/BalUtilUnitTest/precomp.h
+++ b/src/api/burn/test/BalUtilUnitTest/precomp.h
@@ -15,8 +15,8 @@
 #include <dutil.h>
 #include <dictutil.h>
 
-#include <BootstrapperEngine.h>
-#include <BootstrapperApplication.h>
+#include <baenginetypes.h>
+#include <batypes.h>
 
 #include <BAFunctions.h>
 #include <IBootstrapperEngine.h>
diff --git a/src/api/burn/test/WixToolsetTest.Mba.Core/BaseBootstrapperApplicationFactoryFixture.cs b/src/api/burn/test/WixToolsetTest.Mba.Core/BaseBootstrapperApplicationFactoryFixture.cs
deleted file mode 100644
index 7074c166..00000000
--- a/src/api/burn/test/WixToolsetTest.Mba.Core/BaseBootstrapperApplicationFactoryFixture.cs
+++ /dev/null
@@ -1,141 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
-
-namespace WixToolsetTest.Mba.Core
-{
-    using System;
-    using System.Collections.Generic;
-    using System.Runtime.InteropServices;
-    using WixInternal.TestSupport;
-    using WixToolset.Mba.Core;
-    using Xunit;
-
-    public class BaseBootstrapperApplicationFactoryFixture
-    {
-        [Fact]
-        public void CanCreateBA()
-        {
-            var command = new TestCommand
-            {
-                action = LaunchAction.Install,
-                cbSize = Marshal.SizeOf(typeof(TestCommand)),
-                display = Display.Full,
-                wzCommandLine = "this \"is a\" test VariableA=AVariable =EmptyName EmptyValue=",
-            };
-            var pCommand = Marshal.AllocHGlobal(command.cbSize);
-            try
-            {
-                Marshal.StructureToPtr(command, pCommand, false);
-                var createArgs = new BootstrapperCreateArgs(0, IntPtr.Zero, IntPtr.Zero, pCommand);
-                var pArgs = Marshal.AllocHGlobal(createArgs.cbSize);
-                try
-                {
-                    Marshal.StructureToPtr(createArgs, pArgs, false);
-                    var createResults = new TestCreateResults
-                    {
-                        cbSize = Marshal.SizeOf<TestCreateResults>(),
-                    };
-                    var pResults = Marshal.AllocHGlobal(createResults.cbSize);
-                    try
-                    {
-                        var baFactory = new TestBAFactory();
-                        baFactory.Create(pArgs, pResults);
-
-                        createResults = Marshal.PtrToStructure<TestCreateResults>(pResults);
-                        Assert.Equal(baFactory.BA, createResults.pBA);
-                        Assert.Equal(baFactory.BA.Command.Action, command.action);
-                        Assert.Equal(baFactory.BA.Command.Display, command.display);
-
-                        var mbaCommand = baFactory.BA.Command.ParseCommandLine();
-                        WixAssert.CompareLineByLine(mbaCommand.UnknownCommandLineArgs, new string[] { "this", "is a", "test" });
-                        Assert.Equal(mbaCommand.Variables, new KeyValuePair<string, string>[]
-                        {
-                            new KeyValuePair<string, string>("VariableA", "AVariable"),
-                            new KeyValuePair<string, string>("", "EmptyName"),
-                            new KeyValuePair<string, string>("EmptyValue", ""),
-                        });
-                    }
-                    finally
-                    {
-                        Marshal.FreeHGlobal(pResults);
-                    }
-                }
-                finally
-                {
-                    Marshal.FreeHGlobal(pArgs);
-                }
-            }
-            finally
-            {
-                Marshal.FreeHGlobal(pCommand);
-            }
-        }
-
-        internal class TestBAFactory : BaseBootstrapperApplicationFactory
-        {
-            public TestBA BA { get; private set; }
-
-            protected override IBootstrapperApplication Create(IEngine engine, IBootstrapperCommand bootstrapperCommand)
-            {
-                this.BA = new TestBA(engine, bootstrapperCommand);
-                return this.BA;
-            }
-        }
-
-        internal class TestBA : BootstrapperApplication
-        {
-            public IBootstrapperCommand Command { get; }
-
-            public TestBA(IEngine engine, IBootstrapperCommand command)
-                : base(engine)
-            {
-                this.Command = command;
-            }
-
-            protected override void Run()
-            {
-            }
-        }
-
-        [StructLayout(LayoutKind.Sequential)]
-        public struct TestCommand
-        {
-            public int cbSize;
-            public LaunchAction action;
-            public Display display;
-            [MarshalAs(UnmanagedType.LPWStr)] public string wzCommandLine;
-            public int nCmdShow;
-            public ResumeType resume;
-            public IntPtr hwndSplashScreen;
-            public RelationType relation;
-            [MarshalAs(UnmanagedType.Bool)] public bool passthrough;
-            [MarshalAs(UnmanagedType.LPWStr)] public string wzLayoutDirectory;
-        }
-
-        [StructLayout(LayoutKind.Sequential)]
-        public struct BootstrapperCreateArgs
-        {
-            [MarshalAs(UnmanagedType.I4)] public readonly int cbSize;
-            [MarshalAs(UnmanagedType.I8)] public readonly long qwEngineAPIVersion;
-            public readonly IntPtr pfnBootstrapperEngineProc;
-            public readonly IntPtr pvBootstrapperEngineProcContext;
-            public readonly IntPtr pCommand;
-
-            public BootstrapperCreateArgs(long version, IntPtr pEngineProc, IntPtr pEngineContext, IntPtr pCommand)
-            {
-                this.cbSize = Marshal.SizeOf(typeof(BootstrapperCreateArgs));
-                this.qwEngineAPIVersion = version;
-                this.pfnBootstrapperEngineProc = pEngineProc;
-                this.pvBootstrapperEngineProcContext = pEngineContext;
-                this.pCommand = pCommand;
-            }
-        }
-
-        [StructLayout(LayoutKind.Sequential)]
-        public struct TestCreateResults
-        {
-            public int cbSize;
-            public IntPtr pBAProc;
-            [MarshalAs(UnmanagedType.Interface)] public IBootstrapperApplication pBA;
-        }
-    }
-}
diff --git a/src/api/wix/WixToolset.Data/Symbols/SymbolDefinitions.cs b/src/api/wix/WixToolset.Data/Symbols/SymbolDefinitions.cs
index 67c00431..688c34ed 100644
--- a/src/api/wix/WixToolset.Data/Symbols/SymbolDefinitions.cs
+++ b/src/api/wix/WixToolset.Data/Symbols/SymbolDefinitions.cs
@@ -550,8 +550,10 @@ namespace WixToolset.Data
                 case SymbolDefinitionType.WixBootstrapperApplication:
                     return SymbolDefinitions.WixBootstrapperApplication;
 
+#pragma warning disable 612
                 case SymbolDefinitionType.WixBootstrapperApplicationDll:
                     return SymbolDefinitions.WixBootstrapperApplicationDll;
+#pragma warning restore 612
 
                 case SymbolDefinitionType.WixBuildInfo:
                     return SymbolDefinitions.WixBuildInfo;
diff --git a/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperApplicationDllSymbol.cs b/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperApplicationDllSymbol.cs
index d3a66754..250028d0 100644
--- a/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperApplicationDllSymbol.cs
+++ b/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperApplicationDllSymbol.cs
@@ -2,10 +2,12 @@
 
 namespace WixToolset.Data
 {
+    using System;
     using WixToolset.Data.Symbols;
 
     public static partial class SymbolDefinitions
     {
+        [Obsolete]
         public static readonly IntermediateSymbolDefinition WixBootstrapperApplicationDll = new IntermediateSymbolDefinition(
             SymbolDefinitionType.WixBootstrapperApplicationDll,
             new IntermediateFieldDefinition[]
@@ -18,11 +20,14 @@ namespace WixToolset.Data
 
 namespace WixToolset.Data.Symbols
 {
+    using System;
+
     public enum WixBootstrapperApplicationDllSymbolFields
     {
         DpiAwareness,
     }
 
+    [Obsolete]
     public enum WixBootstrapperApplicationDpiAwarenessType
     {
         Unaware,
@@ -32,6 +37,7 @@ namespace WixToolset.Data.Symbols
         GdiScaled,
     }
 
+    [Obsolete]
     public class WixBootstrapperApplicationDllSymbol : IntermediateSymbol
     {
         public WixBootstrapperApplicationDllSymbol() : base(SymbolDefinitions.WixBootstrapperApplicationDll, null, null)
diff --git a/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperApplicationSymbol.cs b/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperApplicationSymbol.cs
index 3d7876fd..abef2cfc 100644
--- a/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperApplicationSymbol.cs
+++ b/src/api/wix/WixToolset.Data/Symbols/WixBootstrapperApplicationSymbol.cs
@@ -10,6 +10,8 @@ namespace WixToolset.Data
             SymbolDefinitionType.WixBootstrapperApplication,
             new IntermediateFieldDefinition[]
             {
+                new IntermediateFieldDefinition(nameof(WixBootstrapperApplicationSymbolFields.ExePayloadRef), IntermediateFieldType.String),
+                new IntermediateFieldDefinition(nameof(WixBootstrapperApplicationSymbolFields.Secondary), IntermediateFieldType.Number),
             },
             typeof(WixBootstrapperApplicationSymbol));
     }
@@ -19,6 +21,8 @@ namespace WixToolset.Data.Symbols
 {
     public enum WixBootstrapperApplicationSymbolFields
     {
+        ExePayloadRef,
+        Secondary
     }
 
     public class WixBootstrapperApplicationSymbol : IntermediateSymbol
@@ -32,5 +36,17 @@ namespace WixToolset.Data.Symbols
         }
 
         public IntermediateField this[WixBootstrapperApplicationSymbolFields index] => this.Fields[(int)index];
+
+        public string ExePayloadRef
+        {
+            get => (string)this.Fields[(int)WixBootstrapperApplicationSymbolFields.ExePayloadRef];
+            set => this.Set((int)WixBootstrapperApplicationSymbolFields.ExePayloadRef, value);
+        }
+
+        public bool? Secondary
+        {
+            get => (bool?)this.Fields[(int)WixBootstrapperApplicationSymbolFields.Secondary];
+            set => this.Set((int)WixBootstrapperApplicationSymbolFields.Secondary, value);
+        }
     }
 }
diff --git a/src/api/wix/WixToolset.Extensibility/Data/IComponentKeyPath.cs b/src/api/wix/WixToolset.Extensibility/Data/IComponentKeyPath.cs
index 2de9c028..cc4f6963 100644
--- a/src/api/wix/WixToolset.Extensibility/Data/IComponentKeyPath.cs
+++ b/src/api/wix/WixToolset.Extensibility/Data/IComponentKeyPath.cs
@@ -2,13 +2,29 @@
 
 namespace WixToolset.Extensibility.Data
 {
-#pragma warning disable 1591 // TODO: add documentation
+    using WixToolset.Data;
+
+    /// <summary>
+    /// Interface used to by extensions to define a component key path or
+    /// (non-intuitively) the executable payload for a the bootstrapper application.
+    /// </summary>
     public interface IComponentKeyPath
     {
+        /// <summary>
+        /// Indicates whether the key path was specified explicitly.
+        /// </summary>
         bool Explicit { get; set; }
 
-        string Id { get; set; }
+        /// <summary>
+        /// Gets or sets the key path or executable payload identifier.
+        /// </summary>
+        Identifier Id { get; set; }
 
+        /// <summary>
+        /// Gets or sets the key path type for the component or if the
+        /// executable payload for a bootstrapper application is provided
+        /// as a File.
+        /// </summary>
         PossibleKeyPathType Type { get; set; }
     }
 }