Better .nupkg names

36 files changed, 10463 insertions, 0 deletions

diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/BalUtil.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/BalUtil.cs
new file mode 100644
index 00000000..25257554
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/BalUtil.cs
@@ -0,0 +1,53 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+
+    internal static class BalUtil
+    {
+        [DllImport("mbanative.dll", ExactSpelling = true)]
+        internal static extern int BalEscapeStringFromEngine(
+            [MarshalAs(UnmanagedType.Interface)] IBootstrapperEngine pEngine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzIn,
+            ref StrUtil.StrHandle psczOut
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true)]
+        internal static extern int BalFormatStringFromEngine(
+            [MarshalAs(UnmanagedType.Interface)] IBootstrapperEngine pEngine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzFormat,
+            ref StrUtil.StrHandle psczOut
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true)]
+        internal static extern int BalGetStringVariableFromEngine(
+            [MarshalAs(UnmanagedType.Interface)] IBootstrapperEngine pEngine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+            ref StrUtil.StrHandle psczOut
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true)]
+        internal static extern int BalGetVersionVariableFromEngine(
+            [MarshalAs(UnmanagedType.Interface)] IBootstrapperEngine pEngine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+            ref StrUtil.StrHandle psczOut
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true)]
+        internal static extern int BalGetRelatedBundleVariableFromEngine(
+            [MarshalAs(UnmanagedType.Interface)] IBootstrapperEngine pEngine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+            ref StrUtil.StrHandle psczOut
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true)]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        internal static extern bool BalVariableExistsFromEngine(
+            [MarshalAs(UnmanagedType.Interface)] IBootstrapperEngine pEngine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable
+            );
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/BaseBootstrapperApplicationFactory.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/BaseBootstrapperApplicationFactory.cs
new file mode 100644
index 00000000..88b136a6
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/BaseBootstrapperApplicationFactory.cs
@@ -0,0 +1,53 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// 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>
+        /// This is no longer used.
+        /// </summary>
+        /// <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)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <summary>
+        /// This is no longer used.
+        /// </summary>
+        /// <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>
+        /// This is no longer used.
+        /// </summary>
+        /// <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)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <summary>
+        /// This is no longer used.
+        /// </summary>
+        /// <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)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperApplication.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperApplication.cs
new file mode 100644
index 00000000..f9fca748
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperApplication.cs
@@ -0,0 +1,2164 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+    using System.Threading;
+
+    /// <summary>
+    /// The default bootstrapper application.
+    /// </summary>
+    [ClassInterface(ClassInterfaceType.None)]
+    public abstract class BootstrapperApplication : MarshalByRefObject, IDefaultBootstrapperApplication
+    {
+        /// <summary>
+        /// Gets the <see cref="IEngine"/> for interaction with the engine.
+        /// </summary>
+        protected IEngine engine;
+
+        /// <inheritdoc/>
+        public event EventHandler<CreateEventArgs> Create;
+
+        /// <inheritdoc/>
+        public event EventHandler<DestroyEventArgs> Destroy;
+
+        /// <inheritdoc/>
+        public event EventHandler<StartupEventArgs> Startup;
+
+        /// <inheritdoc/>
+        public event EventHandler<ShutdownEventArgs> Shutdown;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectBeginEventArgs> DetectBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectForwardCompatibleBundleEventArgs> DetectForwardCompatibleBundle;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectUpdateBeginEventArgs> DetectUpdateBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectUpdateEventArgs> DetectUpdate;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectUpdateCompleteEventArgs> DetectUpdateComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectRelatedBundleEventArgs> DetectRelatedBundle;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectPackageBeginEventArgs> DetectPackageBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectCompatibleMsiPackageEventArgs> DetectCompatibleMsiPackage;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectRelatedMsiPackageEventArgs> DetectRelatedMsiPackage;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectPatchTargetEventArgs> DetectPatchTarget;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectMsiFeatureEventArgs> DetectMsiFeature;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectPackageCompleteEventArgs> DetectPackageComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectCompleteEventArgs> DetectComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanBeginEventArgs> PlanBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanRelatedBundleEventArgs> PlanRelatedBundle;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanRelatedBundleTypeEventArgs> PlanRelatedBundleType;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanRollbackBoundaryEventArgs> PlanRollbackBoundary;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanPackageBeginEventArgs> PlanPackageBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanCompatibleMsiPackageBeginEventArgs> PlanCompatibleMsiPackageBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanCompatibleMsiPackageCompleteEventArgs> PlanCompatibleMsiPackageComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanPatchTargetEventArgs> PlanPatchTarget;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanMsiFeatureEventArgs> PlanMsiFeature;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanMsiPackageEventArgs> PlanMsiPackage;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanPackageCompleteEventArgs> PlanPackageComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlannedCompatiblePackageEventArgs> PlannedCompatiblePackage;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlannedPackageEventArgs> PlannedPackage;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanCompleteEventArgs> PlanComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<ApplyBeginEventArgs> ApplyBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<ElevateBeginEventArgs> ElevateBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<ElevateCompleteEventArgs> ElevateComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<ProgressEventArgs> Progress;
+
+        /// <inheritdoc/>
+        public event EventHandler<ErrorEventArgs> Error;
+
+        /// <inheritdoc/>
+        public event EventHandler<RegisterBeginEventArgs> RegisterBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<RegisterCompleteEventArgs> RegisterComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<UnregisterBeginEventArgs> UnregisterBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<UnregisterCompleteEventArgs> UnregisterComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheBeginEventArgs> CacheBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<CachePackageBeginEventArgs> CachePackageBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheAcquireBeginEventArgs> CacheAcquireBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheAcquireProgressEventArgs> CacheAcquireProgress;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheAcquireResolvingEventArgs> CacheAcquireResolving;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheAcquireCompleteEventArgs> CacheAcquireComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheVerifyBeginEventArgs> CacheVerifyBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheVerifyProgressEventArgs> CacheVerifyProgress;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheVerifyCompleteEventArgs> CacheVerifyComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<CachePackageCompleteEventArgs> CachePackageComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheCompleteEventArgs> CacheComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<ExecuteBeginEventArgs> ExecuteBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<ExecutePackageBeginEventArgs> ExecutePackageBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<ExecutePatchTargetEventArgs> ExecutePatchTarget;
+
+        /// <inheritdoc/>
+        public event EventHandler<ExecuteMsiMessageEventArgs> ExecuteMsiMessage;
+
+        /// <inheritdoc/>
+        public event EventHandler<ExecuteFilesInUseEventArgs> ExecuteFilesInUse;
+
+        /// <inheritdoc/>
+        public event EventHandler<ExecutePackageCompleteEventArgs> ExecutePackageComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<ExecuteCompleteEventArgs> ExecuteComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<ApplyCompleteEventArgs> ApplyComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<ApplyDowngradeEventArgs> ApplyDowngrade;
+
+        /// <inheritdoc/>
+        public event EventHandler<ExecuteProgressEventArgs> ExecuteProgress;
+
+        /// <inheritdoc/>
+        public event EventHandler<LaunchApprovedExeBeginEventArgs> LaunchApprovedExeBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<LaunchApprovedExeCompleteEventArgs> LaunchApprovedExeComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<BeginMsiTransactionBeginEventArgs> BeginMsiTransactionBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<BeginMsiTransactionCompleteEventArgs> BeginMsiTransactionComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<CommitMsiTransactionBeginEventArgs> CommitMsiTransactionBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<CommitMsiTransactionCompleteEventArgs> CommitMsiTransactionComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<RollbackMsiTransactionBeginEventArgs> RollbackMsiTransactionBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<RollbackMsiTransactionCompleteEventArgs> RollbackMsiTransactionComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<PauseAutomaticUpdatesBeginEventArgs> PauseAutomaticUpdatesBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<PauseAutomaticUpdatesCompleteEventArgs> PauseAutomaticUpdatesComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<SystemRestorePointBeginEventArgs> SystemRestorePointBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<SystemRestorePointCompleteEventArgs> SystemRestorePointComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanForwardCompatibleBundleEventArgs> PlanForwardCompatibleBundle;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheContainerOrPayloadVerifyBeginEventArgs> CacheContainerOrPayloadVerifyBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheContainerOrPayloadVerifyProgressEventArgs> CacheContainerOrPayloadVerifyProgress;
+
+        /// <inheritdoc/>
+        public event EventHandler<CacheContainerOrPayloadVerifyCompleteEventArgs> CacheContainerOrPayloadVerifyComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<CachePayloadExtractBeginEventArgs> CachePayloadExtractBegin;
+
+        /// <inheritdoc/>
+        public event EventHandler<CachePayloadExtractProgressEventArgs> CachePayloadExtractProgress;
+
+        /// <inheritdoc/>
+        public event EventHandler<CachePayloadExtractCompleteEventArgs> CachePayloadExtractComplete;
+
+        /// <inheritdoc/>
+        public event EventHandler<PlanRestoreRelatedBundleEventArgs> PlanRestoreRelatedBundle;
+
+        /// <inheritdoc/>
+        public event EventHandler<ExecuteProcessCancelEventArgs> ExecuteProcessCancel;
+
+        /// <inheritdoc/>
+        public event EventHandler<DetectRelatedBundlePackageEventArgs> DetectRelatedBundlePackage;
+
+        /// <inheritdoc/>
+        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="Create"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCreate(CreateEventArgs args)
+        {
+            this.engine = args.Engine;
+
+            EventHandler<CreateEventArgs> handler = this.Create;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <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)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <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)
+            {
+                handler(this, args);
+            }
+
+            Thread uiThread = new Thread(this.Run);
+            uiThread.Name = "UIThread";
+            uiThread.SetApartmentState(ApartmentState.STA);
+            uiThread.Start();
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="Shutdown"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnShutdown(ShutdownEventArgs args)
+        {
+            EventHandler<ShutdownEventArgs> handler = this.Shutdown;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectBegin(DetectBeginEventArgs args)
+        {
+            EventHandler<DetectBeginEventArgs> handler = this.DetectBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectForwardCompatibleBundle"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectForwardCompatibleBundle(DetectForwardCompatibleBundleEventArgs args)
+        {
+            EventHandler<DetectForwardCompatibleBundleEventArgs> handler = this.DetectForwardCompatibleBundle;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectUpdateBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectUpdateBegin(DetectUpdateBeginEventArgs args)
+        {
+            EventHandler<DetectUpdateBeginEventArgs> handler = this.DetectUpdateBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectUpdate"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectUpdate(DetectUpdateEventArgs args)
+        {
+            EventHandler<DetectUpdateEventArgs> handler = this.DetectUpdate;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectUpdateComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectUpdateComplete(DetectUpdateCompleteEventArgs args)
+        {
+            EventHandler<DetectUpdateCompleteEventArgs> handler = this.DetectUpdateComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectRelatedBundle"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectRelatedBundle(DetectRelatedBundleEventArgs args)
+        {
+            EventHandler<DetectRelatedBundleEventArgs> handler = this.DetectRelatedBundle;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectPackageBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectPackageBegin(DetectPackageBeginEventArgs args)
+        {
+            EventHandler<DetectPackageBeginEventArgs> handler = this.DetectPackageBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectCompatibleMsiPackage"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectCompatibleMsiPackage(DetectCompatibleMsiPackageEventArgs args)
+        {
+            EventHandler<DetectCompatibleMsiPackageEventArgs> handler = this.DetectCompatibleMsiPackage;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectRelatedMsiPackage"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectRelatedMsiPackage(DetectRelatedMsiPackageEventArgs args)
+        {
+            EventHandler<DetectRelatedMsiPackageEventArgs> handler = this.DetectRelatedMsiPackage;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectPatchTarget"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectPatchTarget(DetectPatchTargetEventArgs args)
+        {
+            EventHandler<DetectPatchTargetEventArgs> handler = this.DetectPatchTarget;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectMsiFeature"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectMsiFeature(DetectMsiFeatureEventArgs args)
+        {
+            EventHandler<DetectMsiFeatureEventArgs> handler = this.DetectMsiFeature;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectPackageComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectPackageComplete(DetectPackageCompleteEventArgs args)
+        {
+            EventHandler<DetectPackageCompleteEventArgs> handler = this.DetectPackageComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectComplete(DetectCompleteEventArgs args)
+        {
+            EventHandler<DetectCompleteEventArgs> handler = this.DetectComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanBegin(PlanBeginEventArgs args)
+        {
+            EventHandler<PlanBeginEventArgs> handler = this.PlanBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanRelatedBundle"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanRelatedBundle(PlanRelatedBundleEventArgs args)
+        {
+            EventHandler<PlanRelatedBundleEventArgs> handler = this.PlanRelatedBundle;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanRelatedBundleType"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanRelatedBundleType(PlanRelatedBundleTypeEventArgs args)
+        {
+            EventHandler<PlanRelatedBundleTypeEventArgs> handler = this.PlanRelatedBundleType;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanRollbackBoundary"/> event.
+        /// </summary>
+        protected virtual void OnPlanRollbackBoundary(PlanRollbackBoundaryEventArgs args)
+        {
+            EventHandler<PlanRollbackBoundaryEventArgs> handler = this.PlanRollbackBoundary;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanPackageBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanPackageBegin(PlanPackageBeginEventArgs args)
+        {
+            EventHandler<PlanPackageBeginEventArgs> handler = this.PlanPackageBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanCompatibleMsiPackageBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanCompatibleMsiPackageBegin(PlanCompatibleMsiPackageBeginEventArgs args)
+        {
+            EventHandler<PlanCompatibleMsiPackageBeginEventArgs> handler = this.PlanCompatibleMsiPackageBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanCompatibleMsiPackageComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanCompatibleMsiPackageComplete(PlanCompatibleMsiPackageCompleteEventArgs args)
+        {
+            EventHandler<PlanCompatibleMsiPackageCompleteEventArgs> handler = this.PlanCompatibleMsiPackageComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanPatchTarget"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanPatchTarget(PlanPatchTargetEventArgs args)
+        {
+            EventHandler<PlanPatchTargetEventArgs> handler = this.PlanPatchTarget;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanMsiFeature"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanMsiFeature(PlanMsiFeatureEventArgs args)
+        {
+            EventHandler<PlanMsiFeatureEventArgs> handler = this.PlanMsiFeature;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanMsiPackage"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanMsiPackage(PlanMsiPackageEventArgs args)
+        {
+            EventHandler<PlanMsiPackageEventArgs> handler = this.PlanMsiPackage;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanPackageComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanPackageComplete(PlanPackageCompleteEventArgs args)
+        {
+            EventHandler<PlanPackageCompleteEventArgs> handler = this.PlanPackageComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlannedCompatiblePackage"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlannedCompatiblePackage(PlannedCompatiblePackageEventArgs args)
+        {
+            EventHandler<PlannedCompatiblePackageEventArgs> handler = this.PlannedCompatiblePackage;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlannedPackage"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlannedPackage(PlannedPackageEventArgs args)
+        {
+            EventHandler<PlannedPackageEventArgs> handler = this.PlannedPackage;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanComplete(PlanCompleteEventArgs args)
+        {
+            EventHandler<PlanCompleteEventArgs> handler = this.PlanComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ApplyBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnApplyBegin(ApplyBeginEventArgs args)
+        {
+            EventHandler<ApplyBeginEventArgs> handler = this.ApplyBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ElevateBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnElevateBegin(ElevateBeginEventArgs args)
+        {
+            EventHandler<ElevateBeginEventArgs> handler = this.ElevateBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ElevateComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnElevateComplete(ElevateCompleteEventArgs args)
+        {
+            EventHandler<ElevateCompleteEventArgs> handler = this.ElevateComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="Progress"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnProgress(ProgressEventArgs args)
+        {
+            EventHandler<ProgressEventArgs> handler = this.Progress;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="Error"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnError(ErrorEventArgs args)
+        {
+            EventHandler<ErrorEventArgs> handler = this.Error;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="RegisterBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnRegisterBegin(RegisterBeginEventArgs args)
+        {
+            EventHandler<RegisterBeginEventArgs> handler = this.RegisterBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="RegisterComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnRegisterComplete(RegisterCompleteEventArgs args)
+        {
+            EventHandler<RegisterCompleteEventArgs> handler = this.RegisterComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="UnregisterBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnUnregisterBegin(UnregisterBeginEventArgs args)
+        {
+            EventHandler<UnregisterBeginEventArgs> handler = this.UnregisterBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="UnregisterComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnUnregisterComplete(UnregisterCompleteEventArgs args)
+        {
+            EventHandler<UnregisterCompleteEventArgs> handler = this.UnregisterComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheBegin(CacheBeginEventArgs args)
+        {
+            EventHandler<CacheBeginEventArgs> handler = this.CacheBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CachePackageBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCachePackageBegin(CachePackageBeginEventArgs args)
+        {
+            EventHandler<CachePackageBeginEventArgs> handler = this.CachePackageBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheAcquireBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheAcquireBegin(CacheAcquireBeginEventArgs args)
+        {
+            EventHandler<CacheAcquireBeginEventArgs> handler = this.CacheAcquireBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheAcquireProgress"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheAcquireProgress(CacheAcquireProgressEventArgs args)
+        {
+            EventHandler<CacheAcquireProgressEventArgs> handler = this.CacheAcquireProgress;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheAcquireResolving"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheAcquireResolving(CacheAcquireResolvingEventArgs args)
+        {
+            EventHandler<CacheAcquireResolvingEventArgs> handler = this.CacheAcquireResolving;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheAcquireComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheAcquireComplete(CacheAcquireCompleteEventArgs args)
+        {
+            EventHandler<CacheAcquireCompleteEventArgs> handler = this.CacheAcquireComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheVerifyBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheVerifyBegin(CacheVerifyBeginEventArgs args)
+        {
+            EventHandler<CacheVerifyBeginEventArgs> handler = this.CacheVerifyBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheVerifyProgress"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheVerifyProgress(CacheVerifyProgressEventArgs args)
+        {
+            EventHandler<CacheVerifyProgressEventArgs> handler = this.CacheVerifyProgress;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheVerifyComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheVerifyComplete(CacheVerifyCompleteEventArgs args)
+        {
+            EventHandler<CacheVerifyCompleteEventArgs> handler = this.CacheVerifyComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CachePackageComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCachePackageComplete(CachePackageCompleteEventArgs args)
+        {
+            EventHandler<CachePackageCompleteEventArgs> handler = this.CachePackageComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheComplete(CacheCompleteEventArgs args)
+        {
+            EventHandler<CacheCompleteEventArgs> handler = this.CacheComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ExecuteBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnExecuteBegin(ExecuteBeginEventArgs args)
+        {
+            EventHandler<ExecuteBeginEventArgs> handler = this.ExecuteBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ExecutePackageBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnExecutePackageBegin(ExecutePackageBeginEventArgs args)
+        {
+            EventHandler<ExecutePackageBeginEventArgs> handler = this.ExecutePackageBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ExecutePatchTarget"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnExecutePatchTarget(ExecutePatchTargetEventArgs args)
+        {
+            EventHandler<ExecutePatchTargetEventArgs> handler = this.ExecutePatchTarget;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ExecuteMsiMessage"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnExecuteMsiMessage(ExecuteMsiMessageEventArgs args)
+        {
+            EventHandler<ExecuteMsiMessageEventArgs> handler = this.ExecuteMsiMessage;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ExecuteFilesInUse"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnExecuteFilesInUse(ExecuteFilesInUseEventArgs args)
+        {
+            EventHandler<ExecuteFilesInUseEventArgs> handler = this.ExecuteFilesInUse;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ExecutePackageComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnExecutePackageComplete(ExecutePackageCompleteEventArgs args)
+        {
+            EventHandler<ExecutePackageCompleteEventArgs> handler = this.ExecutePackageComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ExecuteComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnExecuteComplete(ExecuteCompleteEventArgs args)
+        {
+            EventHandler<ExecuteCompleteEventArgs> handler = this.ExecuteComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ApplyComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnApplyComplete(ApplyCompleteEventArgs args)
+        {
+            EventHandler<ApplyCompleteEventArgs> handler = this.ApplyComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ApplyDowngrade"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnApplyDowngrade(ApplyDowngradeEventArgs args)
+        {
+            EventHandler<ApplyDowngradeEventArgs> handler = this.ApplyDowngrade;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ExecuteProgress"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnExecuteProgress(ExecuteProgressEventArgs args)
+        {
+            EventHandler<ExecuteProgressEventArgs> handler = this.ExecuteProgress;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="LaunchApprovedExeBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnLaunchApprovedExeBegin(LaunchApprovedExeBeginEventArgs args)
+        {
+            EventHandler<LaunchApprovedExeBeginEventArgs> handler = this.LaunchApprovedExeBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="LaunchApprovedExeComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnLaunchApprovedExeComplete(LaunchApprovedExeCompleteEventArgs args)
+        {
+            EventHandler<LaunchApprovedExeCompleteEventArgs> handler = this.LaunchApprovedExeComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="BeginMsiTransactionBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnBeginMsiTransactionBegin(BeginMsiTransactionBeginEventArgs args)
+        {
+            EventHandler<BeginMsiTransactionBeginEventArgs> handler = this.BeginMsiTransactionBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="BeginMsiTransactionComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnBeginMsiTransactionComplete(BeginMsiTransactionCompleteEventArgs args)
+        {
+            EventHandler<BeginMsiTransactionCompleteEventArgs> handler = this.BeginMsiTransactionComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CommitMsiTransactionBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCommitMsiTransactionBegin(CommitMsiTransactionBeginEventArgs args)
+        {
+            EventHandler<CommitMsiTransactionBeginEventArgs> handler = this.CommitMsiTransactionBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CommitMsiTransactionComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCommitMsiTransactionComplete(CommitMsiTransactionCompleteEventArgs args)
+        {
+            EventHandler<CommitMsiTransactionCompleteEventArgs> handler = this.CommitMsiTransactionComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="RollbackMsiTransactionBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnRollbackMsiTransactionBegin(RollbackMsiTransactionBeginEventArgs args)
+        {
+            EventHandler<RollbackMsiTransactionBeginEventArgs> handler = this.RollbackMsiTransactionBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="RollbackMsiTransactionComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnRollbackMsiTransactionComplete(RollbackMsiTransactionCompleteEventArgs args)
+        {
+            EventHandler<RollbackMsiTransactionCompleteEventArgs> handler = this.RollbackMsiTransactionComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PauseAutomaticUpdatesBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPauseAutomaticUpdatesBegin(PauseAutomaticUpdatesBeginEventArgs args)
+        {
+            EventHandler<PauseAutomaticUpdatesBeginEventArgs> handler = this.PauseAutomaticUpdatesBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PauseAutomaticUpdatesComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPauseAutomaticUpdatesComplete(PauseAutomaticUpdatesCompleteEventArgs args)
+        {
+            EventHandler<PauseAutomaticUpdatesCompleteEventArgs> handler = this.PauseAutomaticUpdatesComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="SystemRestorePointBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnSystemRestorePointBegin(SystemRestorePointBeginEventArgs args)
+        {
+            EventHandler<SystemRestorePointBeginEventArgs> handler = this.SystemRestorePointBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="SystemRestorePointComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnSystemRestorePointComplete(SystemRestorePointCompleteEventArgs args)
+        {
+            EventHandler<SystemRestorePointCompleteEventArgs> handler = this.SystemRestorePointComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanForwardCompatibleBundle"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanForwardCompatibleBundle(PlanForwardCompatibleBundleEventArgs args)
+        {
+            EventHandler<PlanForwardCompatibleBundleEventArgs> handler = this.PlanForwardCompatibleBundle;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheContainerOrPayloadVerifyBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheContainerOrPayloadVerifyBegin(CacheContainerOrPayloadVerifyBeginEventArgs args)
+        {
+            EventHandler<CacheContainerOrPayloadVerifyBeginEventArgs> handler = this.CacheContainerOrPayloadVerifyBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheContainerOrPayloadVerifyProgress"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheContainerOrPayloadVerifyProgress(CacheContainerOrPayloadVerifyProgressEventArgs args)
+        {
+            EventHandler<CacheContainerOrPayloadVerifyProgressEventArgs> handler = this.CacheContainerOrPayloadVerifyProgress;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CacheContainerOrPayloadVerifyComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCacheContainerOrPayloadVerifyComplete(CacheContainerOrPayloadVerifyCompleteEventArgs args)
+        {
+            EventHandler<CacheContainerOrPayloadVerifyCompleteEventArgs> handler = this.CacheContainerOrPayloadVerifyComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CachePayloadExtractBegin"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCachePayloadExtractBegin(CachePayloadExtractBeginEventArgs args)
+        {
+            EventHandler<CachePayloadExtractBeginEventArgs> handler = this.CachePayloadExtractBegin;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CachePayloadExtractProgress"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCachePayloadExtractProgress(CachePayloadExtractProgressEventArgs args)
+        {
+            EventHandler<CachePayloadExtractProgressEventArgs> handler = this.CachePayloadExtractProgress;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CachePayloadExtractComplete"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCachePayloadExtractComplete(CachePayloadExtractCompleteEventArgs args)
+        {
+            EventHandler<CachePayloadExtractCompleteEventArgs> handler = this.CachePayloadExtractComplete;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="PlanRestoreRelatedBundle"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnPlanRestoreRelatedBundle(PlanRestoreRelatedBundleEventArgs args)
+        {
+            EventHandler<PlanRestoreRelatedBundleEventArgs> handler = this.PlanRestoreRelatedBundle;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="ExecuteProcessCancel"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnExecuteProcessCancel(ExecuteProcessCancelEventArgs args)
+        {
+            EventHandler<ExecuteProcessCancelEventArgs> handler = this.ExecuteProcessCancel;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="DetectRelatedBundlePackage"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDetectRelatedBundlePackage(DetectRelatedBundlePackageEventArgs args)
+        {
+            EventHandler<DetectRelatedBundlePackageEventArgs> handler = this.DetectRelatedBundlePackage;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="CachePackageNonVitalValidationFailure"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnCachePackageNonVitalValidationFailure(CachePackageNonVitalValidationFailureEventArgs args)
+        {
+            EventHandler<CachePackageNonVitalValidationFailureEventArgs> handler = this.CachePackageNonVitalValidationFailure;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        #region IBootstrapperApplication Members
+
+        int IBootstrapperApplication.BAProc(int message, IntPtr pvArgs, IntPtr pvResults)
+        {
+            switch (message)
+            {
+                default:
+                    return NativeMethods.E_NOTIMPL;
+            }
+        }
+
+        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()
+        {
+            StartupEventArgs args = new StartupEventArgs();
+            this.OnStartup(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnShutdown(ref BOOTSTRAPPER_SHUTDOWN_ACTION action)
+        {
+            ShutdownEventArgs args = new ShutdownEventArgs(action);
+            this.OnShutdown(args);
+
+            action = args.Action;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectBegin(bool fCached, RegistrationType registrationType, int cPackages, ref bool fCancel)
+        {
+            DetectBeginEventArgs args = new DetectBeginEventArgs(fCached, registrationType, cPackages, fCancel);
+            this.OnDetectBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectForwardCompatibleBundle(string wzBundleId, RelationType relationType, string wzBundleTag, bool fPerMachine, string wzVersion, bool fMissingFromCache, ref bool fCancel)
+        {
+            DetectForwardCompatibleBundleEventArgs args = new DetectForwardCompatibleBundleEventArgs(wzBundleId, relationType, wzBundleTag, fPerMachine, wzVersion, fMissingFromCache, fCancel);
+            this.OnDetectForwardCompatibleBundle(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectUpdateBegin(string wzUpdateLocation, ref bool fCancel, ref bool fSkip)
+        {
+            DetectUpdateBeginEventArgs args = new DetectUpdateBeginEventArgs(wzUpdateLocation, fCancel, fSkip);
+            this.OnDetectUpdateBegin(args);
+
+            fCancel = args.Cancel;
+            fSkip = args.Skip;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectUpdate(string wzUpdateLocation, long dw64Size, string wzHash, UpdateHashType hashAlgorithm, string wzVersion, string wzTitle, string wzSummary, string wzContentType, string wzContent, ref bool fCancel, ref bool fStopProcessingUpdates)
+        {
+            DetectUpdateEventArgs args = new DetectUpdateEventArgs(wzUpdateLocation, dw64Size, wzHash, hashAlgorithm, wzVersion, wzTitle, wzSummary, wzContentType, wzContent, fCancel, fStopProcessingUpdates);
+            this.OnDetectUpdate(args);
+
+            fCancel = args.Cancel;
+            fStopProcessingUpdates = args.StopProcessingUpdates;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectUpdateComplete(int hrStatus, ref bool fIgnoreError)
+        {
+            DetectUpdateCompleteEventArgs args = new DetectUpdateCompleteEventArgs(hrStatus, fIgnoreError);
+            this.OnDetectUpdateComplete(args);
+
+            fIgnoreError = args.IgnoreError;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectRelatedBundle(string wzProductCode, RelationType relationType, string wzBundleTag, bool fPerMachine, string wzVersion, bool fMissingFromCache, ref bool fCancel)
+        {
+            DetectRelatedBundleEventArgs args = new DetectRelatedBundleEventArgs(wzProductCode, relationType, wzBundleTag, fPerMachine, wzVersion, fMissingFromCache, fCancel);
+            this.OnDetectRelatedBundle(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectPackageBegin(string wzPackageId, ref bool fCancel)
+        {
+            DetectPackageBeginEventArgs args = new DetectPackageBeginEventArgs(wzPackageId, fCancel);
+            this.OnDetectPackageBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectCompatibleMsiPackage(string wzPackageId, string wzCompatiblePackageId, string wzCompatiblePackageVersion, ref bool fCancel)
+        {
+            DetectCompatibleMsiPackageEventArgs args = new DetectCompatibleMsiPackageEventArgs(wzPackageId, wzCompatiblePackageId, wzCompatiblePackageVersion, fCancel);
+            this.OnDetectCompatibleMsiPackage(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectRelatedMsiPackage(string wzPackageId, string wzUpgradeCode, string wzProductCode, bool fPerMachine, string wzVersion, RelatedOperation operation, ref bool fCancel)
+        {
+            DetectRelatedMsiPackageEventArgs args = new DetectRelatedMsiPackageEventArgs(wzPackageId, wzUpgradeCode, wzProductCode, fPerMachine, wzVersion, operation, fCancel);
+            this.OnDetectRelatedMsiPackage(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectPatchTarget(string wzPackageId, string wzProductCode, PackageState patchState, ref bool fCancel)
+        {
+            DetectPatchTargetEventArgs args = new DetectPatchTargetEventArgs(wzPackageId, wzProductCode, patchState, fCancel);
+            this.OnDetectPatchTarget(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectMsiFeature(string wzPackageId, string wzFeatureId, FeatureState state, ref bool fCancel)
+        {
+            DetectMsiFeatureEventArgs args = new DetectMsiFeatureEventArgs(wzPackageId, wzFeatureId, state, fCancel);
+            this.OnDetectMsiFeature(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectPackageComplete(string wzPackageId, int hrStatus, PackageState state, bool fCached)
+        {
+            DetectPackageCompleteEventArgs args = new DetectPackageCompleteEventArgs(wzPackageId, hrStatus, state, fCached);
+            this.OnDetectPackageComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectComplete(int hrStatus, bool fEligibleForCleanup)
+        {
+            DetectCompleteEventArgs args = new DetectCompleteEventArgs(hrStatus, fEligibleForCleanup);
+            this.OnDetectComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanBegin(int cPackages, ref bool fCancel)
+        {
+            PlanBeginEventArgs args = new PlanBeginEventArgs(cPackages, fCancel);
+            this.OnPlanBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanRelatedBundle(string wzBundleId, RequestState recommendedState, ref RequestState pRequestedState, ref bool fCancel)
+        {
+            PlanRelatedBundleEventArgs args = new PlanRelatedBundleEventArgs(wzBundleId, recommendedState, pRequestedState, fCancel);
+            this.OnPlanRelatedBundle(args);
+
+            pRequestedState = args.State;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanRelatedBundleType(string wzBundleId, RelatedBundlePlanType recommendedType, ref RelatedBundlePlanType pRequestedType, ref bool fCancel)
+        {
+            PlanRelatedBundleTypeEventArgs args = new PlanRelatedBundleTypeEventArgs(wzBundleId, recommendedType, pRequestedType, fCancel);
+            this.OnPlanRelatedBundleType(args);
+
+            pRequestedType = args.Type;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanRollbackBoundary(string wzRollbackBoundaryId, bool fRecommendedTransaction, ref bool fTransaction, ref bool fCancel)
+        {
+            PlanRollbackBoundaryEventArgs args = new PlanRollbackBoundaryEventArgs(wzRollbackBoundaryId, fRecommendedTransaction, fTransaction, fCancel);
+            this.OnPlanRollbackBoundary(args);
+
+            fTransaction = args.Transaction;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanPackageBegin(string wzPackageId, PackageState state, bool fCached, BOOTSTRAPPER_PACKAGE_CONDITION_RESULT installCondition, BOOTSTRAPPER_PACKAGE_CONDITION_RESULT repairCondition, RequestState recommendedState, BOOTSTRAPPER_CACHE_TYPE recommendedCacheType, ref RequestState pRequestedState, ref BOOTSTRAPPER_CACHE_TYPE pRequestedCacheType, ref bool fCancel)
+        {
+            PlanPackageBeginEventArgs args = new PlanPackageBeginEventArgs(wzPackageId, state, fCached, installCondition, repairCondition, recommendedState, recommendedCacheType, pRequestedState, pRequestedCacheType, fCancel);
+            this.OnPlanPackageBegin(args);
+
+            pRequestedState = args.State;
+            pRequestedCacheType = args.CacheType;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanCompatibleMsiPackageBegin(string wzPackageId, string wzCompatiblePackageId, string wzCompatiblePackageVersion, bool recommendedRemove, ref bool pRequestedRemove, ref bool fCancel)
+        {
+            PlanCompatibleMsiPackageBeginEventArgs args = new PlanCompatibleMsiPackageBeginEventArgs(wzPackageId, wzCompatiblePackageId, wzCompatiblePackageVersion, recommendedRemove, pRequestedRemove, fCancel);
+            this.OnPlanCompatibleMsiPackageBegin(args);
+
+            pRequestedRemove = args.RequestRemove;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanCompatibleMsiPackageComplete(string wzPackageId, string wzCompatiblePackageId, int hrStatus, bool requestedRemove)
+        {
+            PlanCompatibleMsiPackageCompleteEventArgs args = new PlanCompatibleMsiPackageCompleteEventArgs(wzPackageId, wzCompatiblePackageId, hrStatus, requestedRemove);
+            this.OnPlanCompatibleMsiPackageComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanPatchTarget(string wzPackageId, string wzProductCode, RequestState recommendedState, ref RequestState pRequestedState, ref bool fCancel)
+        {
+            PlanPatchTargetEventArgs args = new PlanPatchTargetEventArgs(wzPackageId, wzProductCode, recommendedState, pRequestedState, fCancel);
+            this.OnPlanPatchTarget(args);
+
+            pRequestedState = args.State;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanMsiFeature(string wzPackageId, string wzFeatureId, FeatureState recommendedState, ref FeatureState pRequestedState, ref bool fCancel)
+        {
+            PlanMsiFeatureEventArgs args = new PlanMsiFeatureEventArgs(wzPackageId, wzFeatureId, recommendedState, pRequestedState, fCancel);
+            this.OnPlanMsiFeature(args);
+
+            pRequestedState = args.State;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanMsiPackage(string wzPackageId, bool fExecute, ActionState action, BOOTSTRAPPER_MSI_FILE_VERSIONING recommendedFileVersioning, ref bool fCancel, ref BURN_MSI_PROPERTY actionMsiProperty, ref INSTALLUILEVEL uiLevel, ref bool fDisableExternalUiHandler, ref BOOTSTRAPPER_MSI_FILE_VERSIONING fileVersioning)
+        {
+            PlanMsiPackageEventArgs args = new PlanMsiPackageEventArgs(wzPackageId, fExecute, action, recommendedFileVersioning, fCancel, actionMsiProperty, uiLevel, fDisableExternalUiHandler, fileVersioning);
+            this.OnPlanMsiPackage(args);
+
+            fCancel = args.Cancel;
+            actionMsiProperty = args.ActionMsiProperty;
+            uiLevel = args.UiLevel;
+            fDisableExternalUiHandler = args.DisableExternalUiHandler;
+            fileVersioning = args.FileVersioning;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanPackageComplete(string wzPackageId, int hrStatus, RequestState requested)
+        {
+            var args = new PlanPackageCompleteEventArgs(wzPackageId, hrStatus, requested);
+            this.OnPlanPackageComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlannedCompatiblePackage(string wzPackageId, string wzCompatiblePackageId, bool remove)
+        {
+            var args = new PlannedCompatiblePackageEventArgs(wzPackageId, wzCompatiblePackageId, remove);
+            this.OnPlannedCompatiblePackage(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlannedPackage(string wzPackageId, ActionState execute, ActionState rollback, bool fPlannedCache, bool fPlannedUncache)
+        {
+            var args = new PlannedPackageEventArgs(wzPackageId, execute, rollback, fPlannedCache, fPlannedUncache);
+            this.OnPlannedPackage(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanComplete(int hrStatus)
+        {
+            PlanCompleteEventArgs args = new PlanCompleteEventArgs(hrStatus);
+            this.OnPlanComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnApplyBegin(int dwPhaseCount, ref bool fCancel)
+        {
+            ApplyBeginEventArgs args = new ApplyBeginEventArgs(dwPhaseCount, fCancel);
+            this.OnApplyBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnElevateBegin(ref bool fCancel)
+        {
+            ElevateBeginEventArgs args = new ElevateBeginEventArgs(fCancel);
+            this.OnElevateBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnElevateComplete(int hrStatus)
+        {
+            ElevateCompleteEventArgs args = new ElevateCompleteEventArgs(hrStatus);
+            this.OnElevateComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnProgress(int dwProgressPercentage, int dwOverallPercentage, ref bool fCancel)
+        {
+            ProgressEventArgs args = new ProgressEventArgs(dwProgressPercentage, dwOverallPercentage, fCancel);
+            this.OnProgress(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnError(ErrorType errorType, string wzPackageId, int dwCode, string wzError, int dwUIHint, int cData, string[] rgwzData, Result nRecommendation, ref Result pResult)
+        {
+            ErrorEventArgs args = new ErrorEventArgs(errorType, wzPackageId, dwCode, wzError, dwUIHint, rgwzData, nRecommendation, pResult);
+            this.OnError(args);
+
+            pResult = args.Result;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnRegisterBegin(RegistrationType recommendedRegistrationType, ref bool fCancel, ref RegistrationType registrationType)
+        {
+            RegisterBeginEventArgs args = new RegisterBeginEventArgs(recommendedRegistrationType, fCancel, registrationType);
+            this.OnRegisterBegin(args);
+
+            fCancel = args.Cancel;
+            registrationType = args.RegistrationType;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnRegisterComplete(int hrStatus)
+        {
+            RegisterCompleteEventArgs args = new RegisterCompleteEventArgs(hrStatus);
+            this.OnRegisterComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheBegin(ref bool fCancel)
+        {
+            CacheBeginEventArgs args = new CacheBeginEventArgs(fCancel);
+            this.OnCacheBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCachePackageBegin(string wzPackageId, int cCachePayloads, long dw64PackageCacheSize, bool fVital, ref bool fCancel)
+        {
+            CachePackageBeginEventArgs args = new CachePackageBeginEventArgs(wzPackageId, cCachePayloads, dw64PackageCacheSize, fVital, fCancel);
+            this.OnCachePackageBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheAcquireBegin(string wzPackageOrContainerId, string wzPayloadId, string wzSource, string wzDownloadUrl, string wzPayloadContainerId, CacheOperation recommendation, ref CacheOperation action, ref bool fCancel)
+        {
+            CacheAcquireBeginEventArgs args = new CacheAcquireBeginEventArgs(wzPackageOrContainerId, wzPayloadId, wzSource, wzDownloadUrl, wzPayloadContainerId, recommendation, action, fCancel);
+            this.OnCacheAcquireBegin(args);
+
+            action = args.Action;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheAcquireProgress(string wzPackageOrContainerId, string wzPayloadId, long dw64Progress, long dw64Total, int dwOverallPercentage, ref bool fCancel)
+        {
+            CacheAcquireProgressEventArgs args = new CacheAcquireProgressEventArgs(wzPackageOrContainerId, wzPayloadId, dw64Progress, dw64Total, dwOverallPercentage, fCancel);
+            this.OnCacheAcquireProgress(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheAcquireResolving(string wzPackageOrContainerId, string wzPayloadId, string[] searchPaths, int cSearchPaths, bool fFoundLocal, int dwRecommendedSearchPath, string wzDownloadUrl, string wzPayloadContainerId, CacheResolveOperation recommendation, ref int dwChosenSearchPath, ref CacheResolveOperation action, ref bool fCancel)
+        {
+            CacheAcquireResolvingEventArgs args = new CacheAcquireResolvingEventArgs(wzPackageOrContainerId, wzPayloadId, searchPaths, fFoundLocal, dwRecommendedSearchPath, wzDownloadUrl, wzPayloadContainerId, recommendation, dwChosenSearchPath, action, fCancel);
+            this.OnCacheAcquireResolving(args);
+
+            dwChosenSearchPath = args.ChosenSearchPath;
+            action = args.Action;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheAcquireComplete(string wzPackageOrContainerId, string wzPayloadId, int hrStatus, BOOTSTRAPPER_CACHEACQUIRECOMPLETE_ACTION recommendation, ref BOOTSTRAPPER_CACHEACQUIRECOMPLETE_ACTION action)
+        {
+            CacheAcquireCompleteEventArgs args = new CacheAcquireCompleteEventArgs(wzPackageOrContainerId, wzPayloadId, hrStatus, recommendation, action);
+            this.OnCacheAcquireComplete(args);
+
+            action = args.Action;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheVerifyBegin(string wzPackageOrContainerId, string wzPayloadId, ref bool fCancel)
+        {
+            CacheVerifyBeginEventArgs args = new CacheVerifyBeginEventArgs(wzPackageOrContainerId, wzPayloadId, fCancel);
+            this.OnCacheVerifyBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheVerifyProgress(string wzPackageOrContainerId, string wzPayloadId, long dw64Progress, long dw64Total, int dwOverallPercentage, CacheVerifyStep verifyStep, ref bool fCancel)
+        {
+            CacheVerifyProgressEventArgs args = new CacheVerifyProgressEventArgs(wzPackageOrContainerId, wzPayloadId, dw64Progress, dw64Total, dwOverallPercentage, verifyStep, fCancel);
+            this.OnCacheVerifyProgress(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheVerifyComplete(string wzPackageOrContainerId, string wzPayloadId, int hrStatus, BOOTSTRAPPER_CACHEVERIFYCOMPLETE_ACTION recommendation, ref BOOTSTRAPPER_CACHEVERIFYCOMPLETE_ACTION action)
+        {
+            CacheVerifyCompleteEventArgs args = new CacheVerifyCompleteEventArgs(wzPackageOrContainerId, wzPayloadId, hrStatus, recommendation, action);
+            this.OnCacheVerifyComplete(args);
+
+            action = args.Action;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCachePackageComplete(string wzPackageId, int hrStatus, BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION recommendation, ref BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION action)
+        {
+            CachePackageCompleteEventArgs args = new CachePackageCompleteEventArgs(wzPackageId, hrStatus, recommendation, action);
+            this.OnCachePackageComplete(args);
+
+            action = args.Action;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheComplete(int hrStatus)
+        {
+            CacheCompleteEventArgs args = new CacheCompleteEventArgs(hrStatus);
+            this.OnCacheComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnExecuteBegin(int cExecutingPackages, ref bool fCancel)
+        {
+            ExecuteBeginEventArgs args = new ExecuteBeginEventArgs(cExecutingPackages, fCancel);
+            this.OnExecuteBegin(args);
+
+            args.Cancel = fCancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnExecutePackageBegin(string wzPackageId, bool fExecute, ActionState action, INSTALLUILEVEL uiLevel, bool fDisableExternalUiHandler, ref bool fCancel)
+        {
+            ExecutePackageBeginEventArgs args = new ExecutePackageBeginEventArgs(wzPackageId, fExecute, action, uiLevel, fDisableExternalUiHandler, fCancel);
+            this.OnExecutePackageBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnExecutePatchTarget(string wzPackageId, string wzTargetProductCode, ref bool fCancel)
+        {
+            ExecutePatchTargetEventArgs args = new ExecutePatchTargetEventArgs(wzPackageId, wzTargetProductCode, fCancel);
+            this.OnExecutePatchTarget(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnExecuteProgress(string wzPackageId, int dwProgressPercentage, int dwOverallPercentage, ref bool fCancel)
+        {
+            ExecuteProgressEventArgs args = new ExecuteProgressEventArgs(wzPackageId, dwProgressPercentage, dwOverallPercentage, fCancel);
+            this.OnExecuteProgress(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnExecuteMsiMessage(string wzPackageId, InstallMessage messageType, int dwUIHint, string wzMessage, int cData, string[] rgwzData, Result nRecommendation, ref Result pResult)
+        {
+            ExecuteMsiMessageEventArgs args = new ExecuteMsiMessageEventArgs(wzPackageId, messageType, dwUIHint, wzMessage, rgwzData, nRecommendation, pResult);
+            this.OnExecuteMsiMessage(args);
+
+            pResult = args.Result;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnExecuteFilesInUse(string wzPackageId, int cFiles, string[] rgwzFiles, Result nRecommendation, FilesInUseType source, ref Result pResult)
+        {
+            ExecuteFilesInUseEventArgs args = new ExecuteFilesInUseEventArgs(wzPackageId, rgwzFiles, nRecommendation, source, pResult);
+            this.OnExecuteFilesInUse(args);
+
+            pResult = args.Result;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnExecutePackageComplete(string wzPackageId, int hrStatus, ApplyRestart restart, BOOTSTRAPPER_EXECUTEPACKAGECOMPLETE_ACTION recommendation, ref BOOTSTRAPPER_EXECUTEPACKAGECOMPLETE_ACTION pAction)
+        {
+            ExecutePackageCompleteEventArgs args = new ExecutePackageCompleteEventArgs(wzPackageId, hrStatus, restart, recommendation, pAction);
+            this.OnExecutePackageComplete(args);
+
+            pAction = args.Action;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnExecuteComplete(int hrStatus)
+        {
+            ExecuteCompleteEventArgs args = new ExecuteCompleteEventArgs(hrStatus);
+            this.OnExecuteComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnUnregisterBegin(RegistrationType recommendedRegistrationType, ref RegistrationType registrationType)
+        {
+            UnregisterBeginEventArgs args = new UnregisterBeginEventArgs(recommendedRegistrationType, registrationType);
+            this.OnUnregisterBegin(args);
+
+            registrationType = args.RegistrationType;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnUnregisterComplete(int hrStatus)
+        {
+            UnregisterCompleteEventArgs args = new UnregisterCompleteEventArgs(hrStatus);
+            this.OnUnregisterComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnApplyComplete(int hrStatus, ApplyRestart restart, BOOTSTRAPPER_APPLYCOMPLETE_ACTION recommendation, ref BOOTSTRAPPER_APPLYCOMPLETE_ACTION pAction)
+        {
+            ApplyCompleteEventArgs args = new ApplyCompleteEventArgs(hrStatus, restart, recommendation, pAction);
+            this.OnApplyComplete(args);
+
+            pAction = args.Action;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnApplyDowngrade(int hrRecommendation, ref int hrStatus)
+        {
+            ApplyDowngradeEventArgs args = new ApplyDowngradeEventArgs(hrRecommendation, hrStatus);
+            this.OnApplyDowngrade(args);
+
+            hrStatus = args.Status;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnLaunchApprovedExeBegin(ref bool fCancel)
+        {
+            LaunchApprovedExeBeginEventArgs args = new LaunchApprovedExeBeginEventArgs(fCancel);
+            this.OnLaunchApprovedExeBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnLaunchApprovedExeComplete(int hrStatus, int processId)
+        {
+            LaunchApprovedExeCompleteEventArgs args = new LaunchApprovedExeCompleteEventArgs(hrStatus, processId);
+            this.OnLaunchApprovedExeComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnBeginMsiTransactionBegin(string transactionId, ref bool fCancel)
+        {
+            BeginMsiTransactionBeginEventArgs args = new BeginMsiTransactionBeginEventArgs(transactionId, fCancel);
+            this.OnBeginMsiTransactionBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnBeginMsiTransactionComplete(string transactionId, int hrStatus)
+        {
+            BeginMsiTransactionCompleteEventArgs args = new BeginMsiTransactionCompleteEventArgs(transactionId, hrStatus);
+            this.OnBeginMsiTransactionComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCommitMsiTransactionBegin(string transactionId, ref bool fCancel)
+        {
+            CommitMsiTransactionBeginEventArgs args = new CommitMsiTransactionBeginEventArgs(transactionId, fCancel);
+            this.OnCommitMsiTransactionBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCommitMsiTransactionComplete(string transactionId, int hrStatus, ApplyRestart restart, BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION recommendation, ref BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION pAction)
+        {
+            CommitMsiTransactionCompleteEventArgs args = new CommitMsiTransactionCompleteEventArgs(transactionId, hrStatus, restart, recommendation, pAction);
+            this.OnCommitMsiTransactionComplete(args);
+
+            pAction = args.Action;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnRollbackMsiTransactionBegin(string transactionId)
+        {
+            RollbackMsiTransactionBeginEventArgs args = new RollbackMsiTransactionBeginEventArgs(transactionId);
+            this.OnRollbackMsiTransactionBegin(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnRollbackMsiTransactionComplete(string transactionId, int hrStatus, ApplyRestart restart, BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION recommendation, ref BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION pAction)
+        {
+            RollbackMsiTransactionCompleteEventArgs args = new RollbackMsiTransactionCompleteEventArgs(transactionId, hrStatus, restart, recommendation, pAction);
+            this.OnRollbackMsiTransactionComplete(args);
+
+            pAction = args.Action;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPauseAutomaticUpdatesBegin()
+        {
+            PauseAutomaticUpdatesBeginEventArgs args = new PauseAutomaticUpdatesBeginEventArgs();
+            this.OnPauseAutomaticUpdatesBegin(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPauseAutomaticUpdatesComplete(int hrStatus)
+        {
+            PauseAutomaticUpdatesCompleteEventArgs args = new PauseAutomaticUpdatesCompleteEventArgs(hrStatus);
+            this.OnPauseAutomaticUpdatesComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnSystemRestorePointBegin()
+        {
+            SystemRestorePointBeginEventArgs args = new SystemRestorePointBeginEventArgs();
+            this.OnSystemRestorePointBegin(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnSystemRestorePointComplete(int hrStatus)
+        {
+            SystemRestorePointCompleteEventArgs args = new SystemRestorePointCompleteEventArgs(hrStatus);
+            this.OnSystemRestorePointComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnPlanForwardCompatibleBundle(string wzBundleId, RelationType relationType, string wzBundleTag, bool fPerMachine, string wzVersion, bool fRecommendedIgnoreBundle, ref bool fCancel, ref bool fIgnoreBundle)
+        {
+            PlanForwardCompatibleBundleEventArgs args = new PlanForwardCompatibleBundleEventArgs(wzBundleId, relationType, wzBundleTag, fPerMachine, wzVersion, fRecommendedIgnoreBundle, fCancel, fIgnoreBundle);
+            this.OnPlanForwardCompatibleBundle(args);
+
+            fCancel = args.Cancel;
+            fIgnoreBundle = args.IgnoreBundle;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheContainerOrPayloadVerifyBegin(string wzPackageOrContainerId, string wzPayloadId, ref bool fCancel)
+        {
+            CacheContainerOrPayloadVerifyBeginEventArgs args = new CacheContainerOrPayloadVerifyBeginEventArgs(wzPackageOrContainerId, wzPayloadId, fCancel);
+            this.OnCacheContainerOrPayloadVerifyBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheContainerOrPayloadVerifyProgress(string wzPackageOrContainerId, string wzPayloadId, long dw64Progress, long dw64Total, int dwOverallPercentage, ref bool fCancel)
+        {
+            CacheContainerOrPayloadVerifyProgressEventArgs args = new CacheContainerOrPayloadVerifyProgressEventArgs(wzPackageOrContainerId, wzPayloadId, dw64Progress, dw64Total, dwOverallPercentage, fCancel);
+            this.OnCacheContainerOrPayloadVerifyProgress(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCacheContainerOrPayloadVerifyComplete(string wzPackageOrContainerId, string wzPayloadId, int hrStatus)
+        {
+            CacheContainerOrPayloadVerifyCompleteEventArgs args = new CacheContainerOrPayloadVerifyCompleteEventArgs(wzPackageOrContainerId, wzPayloadId, hrStatus);
+            this.OnCacheContainerOrPayloadVerifyComplete(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCachePayloadExtractBegin(string wzContainerId, string wzPayloadId, ref bool fCancel)
+        {
+            CachePayloadExtractBeginEventArgs args = new CachePayloadExtractBeginEventArgs(wzContainerId, wzPayloadId, fCancel);
+            this.OnCachePayloadExtractBegin(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCachePayloadExtractProgress(string wzContainerId, string wzPayloadId, long dw64Progress, long dw64Total, int dwOverallPercentage, ref bool fCancel)
+        {
+            CachePayloadExtractProgressEventArgs args = new CachePayloadExtractProgressEventArgs(wzContainerId, wzPayloadId, dw64Progress, dw64Total, dwOverallPercentage, fCancel);
+            this.OnCachePayloadExtractProgress(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCachePayloadExtractComplete(string wzContainerId, string wzPayloadId, int hrStatus)
+        {
+            CachePayloadExtractCompleteEventArgs args = new CachePayloadExtractCompleteEventArgs(wzContainerId, wzPayloadId, hrStatus);
+            this.OnCachePayloadExtractComplete(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);
+            this.OnPlanRestoreRelatedBundle(args);
+
+            pRequestedState = args.State;
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnExecuteProcessCancel(string wzPackageId, int processId, BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION recommendation, ref BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION pAction)
+        {
+            ExecuteProcessCancelEventArgs args = new ExecuteProcessCancelEventArgs(wzPackageId, processId, recommendation, pAction);
+            this.OnExecuteProcessCancel(args);
+
+            pAction = args.Action;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDetectRelatedBundlePackage(string wzPackageId, string wzProductCode, RelationType relationType, bool fPerMachine, string wzVersion, ref bool fCancel)
+        {
+            DetectRelatedBundlePackageEventArgs args = new DetectRelatedBundlePackageEventArgs(wzPackageId, wzProductCode, relationType, fPerMachine, wzVersion, fCancel);
+            this.OnDetectRelatedBundlePackage(args);
+
+            fCancel = args.Cancel;
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnCachePackageNonVitalValidationFailure(string wzPackageId, int hrStatus, BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION recommendation, ref BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION action)
+        {
+            CachePackageNonVitalValidationFailureEventArgs args = new CachePackageNonVitalValidationFailureEventArgs(wzPackageId, hrStatus, recommendation, action);
+            this.OnCachePackageNonVitalValidationFailure(args);
+
+            action = args.Action;
+            return args.HResult;
+        }
+
+        #endregion
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperApplicationData.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperApplicationData.cs
new file mode 100644
index 00000000..10cb863f
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperApplicationData.cs
@@ -0,0 +1,101 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.IO;
+    using System.Xml.XPath;
+
+    /// <summary>
+    /// Utility class for reading BootstrapperApplicationData.xml.
+    /// </summary>
+    public class BootstrapperApplicationData : IBootstrapperApplicationData
+    {
+        /// <summary>
+        /// The default file name for BootstrapperApplicationData.
+        /// </summary>
+        public const string DefaultFileName = "BootstrapperApplicationData.xml";
+
+        /// <summary>
+        /// The XML namespace for BootstrapperApplicationData.
+        /// </summary>
+        public const string XMLNamespace = "http://wixtoolset.org/schemas/v4/BootstrapperApplicationData";
+
+        /// <summary>
+        /// The default path of where the BA was extracted to.
+        /// </summary>
+        public static readonly DirectoryInfo DefaultFolder;
+
+        /// <summary>
+        /// The default path to BootstrapperApplicationData.xml.
+        /// </summary>
+        public static readonly FileInfo DefaultFile;
+
+        static BootstrapperApplicationData()
+        {
+            DefaultFolder = new DirectoryInfo(AppDomain.CurrentDomain.BaseDirectory);
+            DefaultFile = new FileInfo(Path.Combine(DefaultFolder.FullName, DefaultFileName));
+        }
+
+        /// <inheritdoc/>
+        public FileInfo BADataFile { get; private set; }
+
+        /// <inheritdoc/>
+        public IBundleInfo Bundle { get; private set; }
+
+        /// <summary>
+        /// Uses the default location for BootstrapperApplicationData.xml.
+        /// </summary>
+        public BootstrapperApplicationData() : this(DefaultFile) { }
+
+        /// <summary>
+        /// Uses the given file for BootstrapperApplicationData.xml.
+        /// </summary>
+        /// <param name="baDataFile"></param>
+        public BootstrapperApplicationData(FileInfo baDataFile)
+        {
+            this.BADataFile = baDataFile;
+
+            using (FileStream fs = this.BADataFile.OpenRead())
+            {
+                this.Bundle = BundleInfo.ParseBundleFromStream(fs);
+            }
+        }
+
+        /// <summary>
+        /// Utility method for parsing BootstrapperApplicationData.xml.
+        /// </summary>
+        /// <param name="node"></param>
+        /// <param name="attributeName"></param>
+        /// <returns></returns>
+        public static string GetAttribute(XPathNavigator node, string attributeName)
+        {
+            XPathNavigator attribute = node.SelectSingleNode("@" + attributeName);
+
+            if (attribute == null)
+            {
+                return null;
+            }
+
+            return attribute.Value;
+        }
+
+        /// <summary>
+        /// Utility method for parsing BootstrapperApplicationData.xml.
+        /// </summary>
+        /// <param name="node"></param>
+        /// <param name="attributeName"></param>
+        /// <returns></returns>
+        public static bool? GetYesNoAttribute(XPathNavigator node, string attributeName)
+        {
+            string attributeValue = GetAttribute(node, attributeName);
+
+            if (attributeValue == null)
+            {
+                return null;
+            }
+
+            return attributeValue.Equals("yes", StringComparison.InvariantCulture);
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperApplicationFactoryAttribute.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperApplicationFactoryAttribute.cs
new file mode 100644
index 00000000..9b64e838
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperApplicationFactoryAttribute.cs
@@ -0,0 +1,31 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+
+    /// <summary>
+    /// 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.")]
+    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = false)]
+    public sealed class BootstrapperApplicationFactoryAttribute : Attribute
+    {
+        /// <summary>
+        /// This is no longer used.
+        /// </summary>
+        /// <param name="bootstrapperApplicationFactoryType">This is no longer used</param>
+        public BootstrapperApplicationFactoryAttribute(Type bootstrapperApplicationFactoryType)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <summary>
+        /// This is no longer used.
+        /// </summary>
+        public Type BootstrapperApplicationFactoryType
+        {
+            get { throw new NotImplementedException(); }
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperCommand.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperCommand.cs
new file mode 100644
index 00000000..612e8ce9
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/BootstrapperCommand.cs
@@ -0,0 +1,239 @@
+// 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.BootstrapperApplicationApi
+{
+    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
+    {
+        /// <summary>
+        /// See <see cref="IBootstrapperCommand"/>.
+        /// </summary>
+        public BootstrapperCommand(
+            LaunchAction action,
+            Display display,
+            string commandLine,
+            int cmdShow,
+            ResumeType resume,
+            IntPtr splashScreen,
+            RelationType relation,
+            bool passthrough,
+            string layoutDirectory,
+            string bootstrapperWorkingFolder,
+            string bootstrapperApplicationDataPath)
+        {
+            this.Action = action;
+            this.Display = display;
+            this.CommandLine = commandLine;
+            this.CmdShow = cmdShow;
+            this.Resume = resume;
+            this.SplashScreen = splashScreen;
+            this.Relation = relation;
+            this.Passthrough = passthrough;
+            this.LayoutDirectory = layoutDirectory;
+            this.BootstrapperWorkingFolder = bootstrapperWorkingFolder;
+            this.BootstrapperApplicationDataPath = bootstrapperApplicationDataPath;
+        }
+
+        /// <inheritdoc/>
+        public LaunchAction Action { get; }
+
+        /// <inheritdoc/>
+        public Display Display { get; }
+
+        /// <inheritdoc/>
+        public string CommandLine { get; }
+
+        /// <inheritdoc/>
+        public int CmdShow { get; }
+
+        /// <inheritdoc/>
+        public ResumeType Resume { get; }
+
+        /// <inheritdoc/>
+        public IntPtr SplashScreen { get; }
+
+        /// <inheritdoc/>
+        public RelationType Relation { get; }
+
+        /// <inheritdoc/>
+        public bool Passthrough { get; }
+
+        /// <inheritdoc/>
+        public string LayoutDirectory { get; }
+
+        /// <inheritdoc/>
+        public string BootstrapperWorkingFolder { get; }
+
+        /// <inheritdoc/>
+        public string BootstrapperApplicationDataPath { get; }
+
+        /// <inheritdoc/>
+        public IMbaCommand ParseCommandLine()
+        {
+            var args = ParseCommandLineToArgs(this.CommandLine);
+            var unknownArgs = new List<string>();
+            var variables = new List<KeyValuePair<string, string>>();
+            var restart = Restart.Unknown;
+
+            foreach (var arg in args)
+            {
+                var unknownArg = false;
+
+                if (arg[0] == '-' || arg[0] == '/')
+                {
+                    var parameter = arg.Substring(1).ToLowerInvariant();
+                    switch (parameter)
+                    {
+                        case "norestart":
+                            if (restart == Restart.Unknown)
+                            {
+                                restart = Restart.Never;
+                            }
+                            break;
+                        case "forcerestart":
+                            if (restart == Restart.Unknown)
+                            {
+                                restart = Restart.Always;
+                            }
+                            break;
+                        default:
+                            unknownArg = true;
+                            break;
+                    }
+                }
+                else
+                {
+                    var index = arg.IndexOf('=');
+                    if (index == -1)
+                    {
+                        unknownArg = true;
+                    }
+                    else
+                    {
+                        var name = arg.Substring(0, index);
+                        var value = arg.Substring(index + 1);
+                        variables.Add(new KeyValuePair<string, string>(name, value));
+                    }
+                }
+
+                if (unknownArg)
+                {
+                    unknownArgs.Add(arg);
+                }
+            }
+
+            if (restart == Restart.Unknown)
+            {
+                restart = this.Display < Display.Full ? Restart.Automatic : Restart.Prompt;
+            }
+
+            return new MbaCommand
+            {
+                Restart = restart,
+                UnknownCommandLineArgs = unknownArgs.ToArray(),
+                Variables = variables.ToArray(),
+            };
+        }
+
+        /// <summary>
+        /// Gets the command line arguments as a string array.
+        /// </summary>
+        /// <returns>
+        /// Array of command line arguments.
+        /// </returns>
+        /// <exception type="Win32Exception">The command line could not be parsed into an array.</exception>
+        /// <remarks>
+        /// This method uses the same parsing as the operating system which handles quotes and spaces correctly.
+        /// </remarks>
+        public static string[] ParseCommandLineToArgs(string commandLine)
+        {
+            if (null == commandLine)
+            {
+                return new string[0];
+            }
+
+            // Parse the filtered command line arguments into a native array.
+            int argc = 0;
+
+            // CommandLineToArgvW tries to treat the first argument as the path to the process,
+            // which fails pretty miserably if your first argument is something like
+            // FOO="C:\Program Files\My Company". So give it something harmless to play with.
+            IntPtr argv = NativeMethods.CommandLineToArgvW("ignored " + commandLine, out argc);
+
+            if (IntPtr.Zero == argv)
+            {
+                // Throw an exception with the last error.
+                throw new Win32Exception();
+            }
+
+            // Marshal each native array pointer to a managed string.
+            try
+            {
+                // Skip "ignored" argument/hack.
+                string[] args = new string[argc - 1];
+                for (int i = 1; i < argc; ++i)
+                {
+                    IntPtr argvi = Marshal.ReadIntPtr(argv, i * IntPtr.Size);
+                    args[i - 1] = Marshal.PtrToStringUni(argvi);
+                }
+
+                return args;
+            }
+            finally
+            {
+                NativeMethods.LocalFree(argv);
+            }
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/BundleInfo.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/BundleInfo.cs
new file mode 100644
index 00000000..14cac881
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/BundleInfo.cs
@@ -0,0 +1,99 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Collections.Generic;
+    using System.IO;
+    using System.Xml;
+    using System.Xml.XPath;
+
+    /// <summary>
+    /// Default implementation of <see cref="IBundleInfo"/>.
+    /// </summary>
+    public class BundleInfo : IBundleInfo
+    {
+        /// <inheritdoc/>
+        public bool PerMachine { get; internal set; }
+
+        /// <inheritdoc/>
+        public string Name { get; internal set; }
+
+        /// <inheritdoc/>
+        public string LogVariable { get; internal set; }
+
+        /// <inheritdoc/>
+        public IOverridableVariables OverridableVariables { get; internal set; }
+
+        /// <inheritdoc/>
+        public IDictionary<string, IPackageInfo> Packages { get; internal set; }
+
+        internal BundleInfo()
+        {
+            this.Packages = new Dictionary<string, IPackageInfo>();
+        }
+
+        /// <inheritdoc/>
+        public IPackageInfo AddRelatedBundleAsPackage(string productCode, RelationType relationType, bool perMachine, string version)
+        {
+            var package = PackageInfo.GetRelatedBundleAsPackage(productCode, relationType, perMachine, version);
+            this.Packages.Add(package.Id, package);
+            return package;
+        }
+
+        /// <inheritdoc/>
+        public IPackageInfo AddUpdateBundleAsPackage(string packageId)
+        {
+            var package = PackageInfo.GetUpdateBundleAsPackage(packageId);
+            this.Packages.Add(package.Id, package);
+            return package;
+        }
+
+        /// <summary>
+        /// Parses BA manifest from the given stream.
+        /// </summary>
+        /// <param name="stream"></param>
+        /// <returns></returns>
+        public static IBundleInfo ParseBundleFromStream(Stream stream)
+        {
+            XPathDocument manifest = new XPathDocument(stream);
+            XPathNavigator root = manifest.CreateNavigator();
+            return ParseBundleFromXml(root);
+        }
+
+        /// <summary>
+        /// Parses BA manifest from the given <see cref="XPathNavigator"/>.
+        /// </summary>
+        /// <param name="root">The root of the BA manifest.</param>
+        /// <returns></returns>
+        public static IBundleInfo ParseBundleFromXml(XPathNavigator root)
+        {
+            BundleInfo bundle = new BundleInfo();
+
+            XmlNamespaceManager namespaceManager = new XmlNamespaceManager(root.NameTable);
+            namespaceManager.AddNamespace("p", BootstrapperApplicationData.XMLNamespace);
+            XPathNavigator bundleNode = root.SelectSingleNode("/p:BootstrapperApplicationData/p:WixBundleProperties", namespaceManager);
+
+            if (bundleNode == null)
+            {
+                throw new Exception("Failed to select bundle information.");
+            }
+
+            bool? perMachine = BootstrapperApplicationData.GetYesNoAttribute(bundleNode, "PerMachine");
+            if (perMachine.HasValue)
+            {
+                bundle.PerMachine = perMachine.Value;
+            }
+
+            bundle.Name = BootstrapperApplicationData.GetAttribute(bundleNode, "DisplayName");
+
+            bundle.LogVariable = BootstrapperApplicationData.GetAttribute(bundleNode, "LogPathVariable");
+
+            bundle.OverridableVariables = OverridableVariablesInfo.ParseFromXml(root);
+
+            bundle.Packages = PackageInfo.ParsePackagesFromXml(root);
+
+            return bundle;
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/Engine.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/Engine.cs
new file mode 100644
index 00000000..487858e0
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/Engine.cs
@@ -0,0 +1,349 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.ComponentModel;
+    using System.Runtime.InteropServices;
+    using System.Security;
+
+    /// <summary>
+    /// Default implementation of <see cref="IEngine"/>.
+    /// </summary>
+    public sealed class Engine : IEngine
+    {
+        private IBootstrapperEngine engine;
+
+        internal Engine(IBootstrapperEngine engine)
+        {
+            this.engine = engine;
+        }
+
+        /// <inheritdoc/>
+        public int PackageCount
+        {
+            get
+            {
+                int count;
+                this.engine.GetPackageCount(out count);
+
+                return count;
+            }
+        }
+
+        /// <inheritdoc/>
+        public void Apply(IntPtr hwndParent)
+        {
+            this.engine.Apply(hwndParent);
+        }
+
+        /// <inheritdoc/>
+        public void CloseSplashScreen()
+        {
+            this.engine.CloseSplashScreen();
+        }
+
+        /// <inheritdoc/>
+        public int CompareVersions(string version1, string version2)
+        {
+            this.engine.CompareVersions(version1, version2, out var result);
+            return result;
+        }
+
+        /// <inheritdoc/>
+        public bool ContainsVariable(string name)
+        {
+            return BalUtil.BalVariableExistsFromEngine(this.engine, name);
+        }
+
+        /// <inheritdoc/>
+        public void Detect()
+        {
+            this.Detect(IntPtr.Zero);
+        }
+
+        /// <inheritdoc/>
+        public void Detect(IntPtr hwndParent)
+        {
+            this.engine.Detect(hwndParent);
+        }
+
+        /// <inheritdoc/>
+        public bool Elevate(IntPtr hwndParent)
+        {
+            int ret = this.engine.Elevate(hwndParent);
+
+            if (NativeMethods.S_OK == ret || NativeMethods.E_ALREADYINITIALIZED == ret)
+            {
+                return true;
+            }
+            else if (NativeMethods.E_CANCELLED == ret)
+            {
+                return false;
+            }
+            else
+            {
+                throw new Win32Exception(ret);
+            }
+        }
+
+        /// <inheritdoc/>
+        public string EscapeString(string input)
+        {
+            StrUtil.StrHandle handle = new StrUtil.StrHandle();
+            try
+            {
+                int ret = BalUtil.BalEscapeStringFromEngine(this.engine, input, ref handle);
+                if (ret != NativeMethods.S_OK)
+                {
+                    throw new Win32Exception(ret);
+                }
+
+                return handle.ToUniString();
+            }
+            finally
+            {
+                handle.Dispose();
+            }
+        }
+
+        /// <inheritdoc/>
+        public bool EvaluateCondition(string condition)
+        {
+            bool value;
+            this.engine.EvaluateCondition(condition, out value);
+
+            return value;
+        }
+
+        /// <inheritdoc/>
+        public string FormatString(string format)
+        {
+            StrUtil.StrHandle handle = new StrUtil.StrHandle();
+            try
+            {
+                int ret = BalUtil.BalFormatStringFromEngine(this.engine, format, ref handle);
+                if (ret != NativeMethods.S_OK)
+                {
+                    throw new Win32Exception(ret);
+                }
+
+                return handle.ToUniString();
+            }
+            finally
+            {
+                handle.Dispose();
+            }
+        }
+
+        /// <inheritdoc/>
+        public long GetVariableNumeric(string name)
+        {
+            int ret = this.engine.GetVariableNumeric(name, out long value);
+            if (NativeMethods.S_OK != ret)
+            {
+                throw new Win32Exception(ret);
+            }
+
+            return value;
+        }
+
+        /// <inheritdoc/>
+        public SecureString GetVariableSecureString(string name)
+        {
+            StrUtil.StrHandle handle = new StrUtil.StrHandle();
+            try
+            {
+                int ret = BalUtil.BalGetStringVariableFromEngine(this.engine, name, ref handle);
+                if (ret != NativeMethods.S_OK)
+                {
+                    throw new Win32Exception(ret);
+                }
+
+                return handle.ToSecureString();
+            }
+            finally
+            {
+                handle.Dispose();
+            }
+        }
+
+        /// <inheritdoc/>
+        public string GetVariableString(string name)
+        {
+            StrUtil.StrHandle handle = new StrUtil.StrHandle();
+            try
+            {
+                int ret = BalUtil.BalGetStringVariableFromEngine(this.engine, name, ref handle);
+                if (ret != NativeMethods.S_OK)
+                {
+                    throw new Win32Exception(ret);
+                }
+
+                return handle.ToUniString();
+            }
+            finally
+            {
+                handle.Dispose();
+            }
+        }
+
+        /// <inheritdoc/>
+        public string GetVariableVersion(string name)
+        {
+            StrUtil.StrHandle handle = new StrUtil.StrHandle();
+            try
+            {
+                int ret = BalUtil.BalGetVersionVariableFromEngine(this.engine, name, ref handle);
+                if (ret != NativeMethods.S_OK)
+                {
+                    throw new Win32Exception(ret);
+                }
+
+                return handle.ToUniString();
+            }
+            finally
+            {
+                handle.Dispose();
+            }
+        }
+
+        /// <inheritdoc/>
+        public string GetRelatedBundleVariable(string bundleId, string name)
+        {
+            StrUtil.StrHandle handle = new StrUtil.StrHandle();
+            try
+            {
+                int ret = BalUtil.BalGetRelatedBundleVariableFromEngine(this.engine, bundleId, name, ref handle);
+                if (ret != NativeMethods.S_OK)
+                {
+                    throw new Win32Exception(ret);
+                }
+
+                return handle.ToUniString();
+            }
+            finally
+            {
+                handle.Dispose();
+            }
+        }
+
+        /// <inheritdoc/>
+        public void LaunchApprovedExe(IntPtr hwndParent, string approvedExeForElevationId, string arguments)
+        {
+            this.LaunchApprovedExe(hwndParent, approvedExeForElevationId, arguments, 0);
+        }
+
+        /// <inheritdoc/>
+        public void LaunchApprovedExe(IntPtr hwndParent, string approvedExeForElevationId, string arguments, int waitForInputIdleTimeout)
+        {
+            this.engine.LaunchApprovedExe(hwndParent, approvedExeForElevationId, arguments, waitForInputIdleTimeout);
+        }
+        /// <inheritdoc/>
+
+        public void Log(LogLevel level, string message)
+        {
+            this.engine.Log(level, message);
+        }
+
+        /// <inheritdoc/>
+        public void Plan(LaunchAction action)
+        {
+            this.engine.Plan(action);
+        }
+
+        /// <inheritdoc/>
+        public void SetUpdate(string localSource, string downloadSource, long size, UpdateHashType hashType, string hash, string updatePackageId)
+        {
+            this.engine.SetUpdate(localSource, downloadSource, size, hashType, hash, updatePackageId);
+        }
+
+        /// <inheritdoc/>
+        public void SetUpdateSource(string url)
+        {
+            this.engine.SetUpdateSource(url);
+        }
+
+        /// <inheritdoc/>
+        public void SetLocalSource(string packageOrContainerId, string payloadId, string path)
+        {
+            this.engine.SetLocalSource(packageOrContainerId, payloadId, path);
+        }
+
+        /// <inheritdoc/>
+        public void SetDownloadSource(string packageOrContainerId, string payloadId, string url, string user, string password)
+        {
+            this.engine.SetDownloadSource(packageOrContainerId, payloadId, url, user, password);
+        }
+
+        /// <inheritdoc/>
+        public void SetVariableNumeric(string name, long value)
+        {
+            this.engine.SetVariableNumeric(name, value);
+        }
+
+        /// <inheritdoc/>
+        public void SetVariableString(string name, SecureString value, bool formatted)
+        {
+            IntPtr pValue = Marshal.SecureStringToCoTaskMemUnicode(value);
+            try
+            {
+                this.engine.SetVariableString(name, pValue, formatted);
+            }
+            finally
+            {
+                Marshal.FreeCoTaskMem(pValue);
+            }
+        }
+
+        /// <inheritdoc/>
+        public void SetVariableString(string name, string value, bool formatted)
+        {
+            IntPtr pValue = Marshal.StringToCoTaskMemUni(value);
+            try
+            {
+                this.engine.SetVariableString(name, pValue, formatted);
+            }
+            finally
+            {
+                Marshal.FreeCoTaskMem(pValue);
+            }
+        }
+
+        /// <inheritdoc/>
+        public void SetVariableVersion(string name, string value)
+        {
+            IntPtr pValue = Marshal.StringToCoTaskMemUni(value);
+            try
+            {
+                this.engine.SetVariableVersion(name, pValue);
+            }
+            finally
+            {
+                Marshal.FreeCoTaskMem(pValue);
+            }
+        }
+
+        /// <inheritdoc/>
+        public int SendEmbeddedError(int errorCode, string message, int uiHint)
+        {
+            int result = 0;
+            this.engine.SendEmbeddedError(errorCode, message, uiHint, out result);
+            return result;
+        }
+
+        /// <inheritdoc/>
+        public int SendEmbeddedProgress(int progressPercentage, int overallPercentage)
+        {
+            int result = 0;
+            this.engine.SendEmbeddedProgress(progressPercentage, overallPercentage, out result);
+            return result;
+        }
+
+        /// <inheritdoc/>
+        public void Quit(int exitCode)
+        {
+            this.engine.Quit(exitCode);
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/EventArgs.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/EventArgs.cs
new file mode 100644
index 00000000..e1649d43
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/EventArgs.cs
@@ -0,0 +1,2757 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Collections.ObjectModel;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// Base class for BA <see cref="EventArgs"/> classes.
+    /// </summary>
+    [Serializable]
+    public abstract class HResultEventArgs : EventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public HResultEventArgs()
+        {
+        }
+
+        /// <summary>
+        /// Gets or sets the <see cref="HResult"/> of the operation. This is passed back to the engine.
+        /// </summary>
+        public int HResult { get; set; }
+    }
+
+    /// <summary>
+    /// Base class for cancellable BA <see cref="EventArgs"/> classes.
+    /// </summary>
+    [Serializable]
+    public abstract class CancellableHResultEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CancellableHResultEventArgs(bool cancelRecommendation)
+        {
+            this.Cancel = cancelRecommendation;
+        }
+
+        /// <summary>
+        /// Gets or sets whether to cancel the operation. This is passed back to the engine.
+        /// </summary>
+        public bool Cancel { get; set; }
+    }
+
+    /// <summary>
+    /// Base class for <see cref="EventArgs"/> classes that must return a <see cref="Result"/>.
+    /// </summary>
+    [Serializable]
+    public abstract class ResultEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ResultEventArgs(Result recommendation, Result result)
+        {
+            this.Recommendation = recommendation;
+            this.Result = result;
+        }
+
+        /// <summary>
+        /// Gets the recommended <see cref="Result"/> of the operation.
+        /// </summary>
+        public Result Recommendation { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the <see cref="Result"/> of the operation. This is passed back to the engine.
+        /// </summary>
+        public Result Result { get; set; }
+    }
+
+    /// <summary>
+    /// Base class for <see cref="EventArgs"/> classes that receive status from the engine.
+    /// </summary>
+    [Serializable]
+    public abstract class StatusEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public StatusEventArgs(int hrStatus)
+        {
+            this.Status = hrStatus;
+        }
+
+        /// <summary>
+        /// Gets the return code of the operation.
+        /// </summary>
+        public int Status { get; private set; }
+    }
+
+    /// <summary>
+    /// Base class for <see cref="EventArgs"/> classes that receive status from the engine and return an action.
+    /// </summary>
+    public abstract class ActionEventArgs<T> : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ActionEventArgs(int hrStatus, T recommendation, T action)
+            : base(hrStatus)
+        {
+            this.Recommendation = recommendation;
+            this.Action = action;
+        }
+
+        /// <summary>
+        /// Gets the recommended action from the engine.
+        /// </summary>
+        public T Recommendation { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the action to be performed. This is passed back to the engine.
+        /// </summary>
+        public T Action { get; set; }
+    }
+
+    /// <summary>
+    /// Base class for cancellable action BA <see cref="EventArgs"/> classes.
+    /// </summary>
+    [Serializable]
+    public abstract class CancellableActionEventArgs<T> : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CancellableActionEventArgs(bool cancelRecommendation, T recommendation, T action)
+            : base(cancelRecommendation)
+        {
+            this.Recommendation = recommendation;
+            this.Action = action;
+        }
+
+        /// <summary>
+        /// Gets the recommended action from the engine.
+        /// </summary>
+        public T Recommendation { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the action to be performed. This is passed back to the engine.
+        /// </summary>
+        public T Action { get; set; }
+    }
+
+    /// <summary>
+    /// Base class for cache progress events.
+    /// </summary>
+    [Serializable]
+    public abstract class CacheProgressBaseEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheProgressBaseEventArgs(string packageOrContainerId, string payloadId, long progress, long total, int overallPercentage, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageOrContainerId = packageOrContainerId;
+            this.PayloadId = payloadId;
+            this.Progress = progress;
+            this.Total = total;
+            this.OverallPercentage = overallPercentage;
+        }
+
+        /// <summary>
+        /// Gets the identifier of the container or package.
+        /// </summary>
+        public string PackageOrContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identifier of the payload.
+        /// </summary>
+        public string PayloadId { get; private set; }
+
+        /// <summary>
+        /// Gets the number of bytes cached thus far.
+        /// </summary>
+        public long Progress { get; private set; }
+
+        /// <summary>
+        /// Gets the total bytes to cache.
+        /// </summary>
+        public long Total { get; private set; }
+
+        /// <summary>
+        /// Gets the overall percentage of progress of caching.
+        /// </summary>
+        public int OverallPercentage { get; private set; }
+    }
+
+    /// <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]
+    public class StartupEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public StartupEventArgs()
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.Shutdown"/>.
+    /// </summary>
+    [Serializable]
+    public class ShutdownEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ShutdownEventArgs(BOOTSTRAPPER_SHUTDOWN_ACTION action)
+        {
+            this.Action = action;
+        }
+
+        /// <summary>
+        /// The action for OnShutdown.
+        /// </summary>
+        public BOOTSTRAPPER_SHUTDOWN_ACTION Action { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectBegin"/>
+    /// </summary>
+    [Serializable]
+    public class DetectBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectBeginEventArgs(bool cached, RegistrationType registrationType, int packageCount, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.Cached = cached;
+            this.RegistrationType = registrationType;
+            this.PackageCount = packageCount;
+        }
+
+        /// <summary>
+        /// Gets whether the bundle is cached.
+        /// </summary>
+        public bool Cached { get; private set; }
+
+        /// <summary>
+        /// Gets the bundle's registration state.
+        /// </summary>
+        public RegistrationType RegistrationType { get; private set; }
+
+        /// <summary>
+        /// Gets the number of packages to detect.
+        /// </summary>
+        public int PackageCount { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectForwardCompatibleBundle"/>
+    /// </summary>
+    [Serializable]
+    public class DetectForwardCompatibleBundleEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectForwardCompatibleBundleEventArgs(string bundleId, RelationType relationType, string bundleTag, bool perMachine, string version, bool missingFromCache, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.BundleId = bundleId;
+            this.RelationType = relationType;
+            this.BundleTag = bundleTag;
+            this.PerMachine = perMachine;
+            this.Version = version;
+            this.MissingFromCache = missingFromCache;
+        }
+
+        /// <summary>
+        /// Gets the identity of the forward compatible bundle detected.
+        /// </summary>
+        public string BundleId { get; private set; }
+
+        /// <summary>
+        /// Gets the relationship type of the forward compatible bundle.
+        /// </summary>
+        public RelationType RelationType { get; private set; }
+
+        /// <summary>
+        /// Gets the tag of the forward compatible bundle.
+        /// </summary>
+        public string BundleTag { get; private set; }
+
+        /// <summary>
+        /// Gets whether the detected forward compatible bundle is per machine.
+        /// </summary>
+        public bool PerMachine { get; private set; }
+
+        /// <summary>
+        /// Gets the version of the forward compatible bundle detected.
+        /// </summary>
+        public string Version { get; private set; }
+
+        /// <summary>
+        /// Whether the forward compatible bundle is missing from the package cache.
+        /// </summary>
+        public bool MissingFromCache { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectUpdateBegin"/>
+    /// </summary>
+    [Serializable]
+    public class DetectUpdateBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectUpdateBeginEventArgs(string updateLocation, bool cancelRecommendation, bool skipRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.UpdateLocation = updateLocation;
+            this.Skip = skipRecommendation;
+        }
+
+        /// <summary>
+        /// Gets the identity of the bundle to detect.
+        /// </summary>
+        public string UpdateLocation { get; private set; }
+
+        /// <summary>
+        /// Whether to skip checking for bundle updates.
+        /// </summary>
+        public bool Skip { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectUpdate"/>
+    /// </summary>
+    [Serializable]
+    public class DetectUpdateEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectUpdateEventArgs(string updateLocation, long size, string hash, UpdateHashType hashAlgorithm, string version, string title, string summary, string contentType, string content, bool cancelRecommendation, bool stopRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.UpdateLocation = updateLocation;
+            this.Size = size;
+            this.Hash = hash;
+            this.HashAlgorithm = hashAlgorithm;
+            this.Version = version;
+            this.Title = title;
+            this.Summary = summary;
+            this.ContentType = contentType;
+            this.Content = content;
+            this.StopProcessingUpdates = stopRecommendation;
+        }
+
+        /// <summary>
+        /// Gets the identity of the bundle to detect.
+        /// </summary>
+        public string UpdateLocation { get; private set; }
+
+        /// <summary>
+        /// Gets the size of the updated bundle.
+        /// </summary>
+        public long Size { get; private set; }
+
+        /// <summary>
+        /// File hash of the updated bundle.
+        /// </summary>
+        public string Hash { get; }
+
+        /// <summary>
+        /// The algorithm of the updated bundle's hash.
+        /// </summary>
+        public UpdateHashType HashAlgorithm { get; }
+
+        /// <summary>
+        /// Gets the version of the updated bundle.
+        /// </summary>
+        public string Version { get; private set; }
+
+        /// <summary>
+        /// Gets the title of the the updated bundle.
+        /// </summary>
+        public string Title { get; private set; }
+
+        /// <summary>
+        /// Gets the summary of the updated bundle.
+        /// </summary>
+        public string Summary { get; private set; }
+
+        /// <summary>
+        /// Gets the content type of the content of the updated bundle.
+        /// </summary>
+        public string ContentType { get; private set; }
+
+        /// <summary>
+        /// Gets the content of the updated bundle.
+        /// </summary>
+        public string Content { get; private set; }
+
+        /// <summary>
+        /// Tells the engine to stop giving the rest of the updates found in the feed.
+        /// </summary>
+        public bool StopProcessingUpdates { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectUpdateComplete"/>
+    /// </summary>
+    [Serializable]
+    public class DetectUpdateCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectUpdateCompleteEventArgs(int hrStatus, bool ignoreRecommendation)
+            : base(hrStatus)
+        {
+            this.IgnoreError = ignoreRecommendation;
+        }
+
+        /// <summary>
+        /// If Status is an error, then set this to true to ignore it and continue detecting.
+        /// </summary>
+        public bool IgnoreError { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectRelatedBundle"/>
+    /// </summary>
+    [Serializable]
+    public class DetectRelatedBundleEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectRelatedBundleEventArgs(string productCode, RelationType relationType, string bundleTag, bool perMachine, string version, bool missingFromCache, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.ProductCode = productCode;
+            this.RelationType = relationType;
+            this.BundleTag = bundleTag;
+            this.PerMachine = perMachine;
+            this.Version = version;
+            this.MissingFromCache = missingFromCache;
+        }
+
+        /// <summary>
+        /// Gets the identity of the related bundle detected.
+        /// </summary>
+        public string ProductCode { get; private set; }
+
+        /// <summary>
+        /// Gets the relationship type of the related bundle.
+        /// </summary>
+        public RelationType RelationType { get; private set; }
+
+        /// <summary>
+        /// Gets the tag of the related package bundle.
+        /// </summary>
+        public string BundleTag { get; private set; }
+
+        /// <summary>
+        /// Gets whether the detected bundle is per machine.
+        /// </summary>
+        public bool PerMachine { get; private set; }
+
+        /// <summary>
+        /// Gets the version of the related bundle detected.
+        /// </summary>
+        public string Version { get; private set; }
+
+        /// <summary>
+        /// Whether the related bundle is missing from the package cache.
+        /// </summary>
+        public bool MissingFromCache { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectPackageBegin"/>
+    /// </summary>
+    [Serializable]
+    public class DetectPackageBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectPackageBeginEventArgs(string packageId, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package to detect.
+        /// </summary>
+        public string PackageId { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectCompatibleMsiPackage"/>
+    /// </summary>
+    [Serializable]
+    public class DetectCompatibleMsiPackageEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectCompatibleMsiPackageEventArgs(string packageId, string compatiblePackageId, string compatiblePackageVersion, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.CompatiblePackageId = compatiblePackageId;
+            this.CompatiblePackageVersion = compatiblePackageVersion;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package that was not detected.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the compatible package that was detected.
+        /// </summary>
+        public string CompatiblePackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the version of the compatible package that was detected.
+        /// </summary>
+        public string CompatiblePackageVersion { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectRelatedMsiPackage"/>
+    /// </summary>
+    [Serializable]
+    public class DetectRelatedMsiPackageEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectRelatedMsiPackageEventArgs(string packageId, string upgradeCode, string productCode, bool perMachine, string version, RelatedOperation operation, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.UpgradeCode = upgradeCode;
+            this.ProductCode = productCode;
+            this.PerMachine = perMachine;
+            this.Version = version;
+            this.Operation = operation;
+        }
+
+        /// <summary>
+        /// Gets the identity of the product's package detected.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the upgrade code of the related package detected.
+        /// </summary>
+        public string UpgradeCode { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the related package detected.
+        /// </summary>
+        public string ProductCode { get; private set; }
+
+        /// <summary>
+        /// Gets whether the detected package is per machine.
+        /// </summary>
+        public bool PerMachine { get; private set; }
+
+        /// <summary>
+        /// Gets the version of the related package detected.
+        /// </summary>
+        public string Version { get; private set; }
+
+        /// <summary>
+        /// Gets the operation that will be taken on the detected package.
+        /// </summary>
+        public RelatedOperation Operation { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectPatchTarget"/>
+    /// </summary>
+    public class DetectPatchTargetEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectPatchTargetEventArgs(string packageId, string productCode, PackageState state, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.ProductCode = productCode;
+            this.State = state;
+        }
+
+        /// <summary>
+        /// Gets the identity of the patch's package.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the product code of the target.
+        /// </summary>
+        public string ProductCode { get; private set; }
+
+        /// <summary>
+        /// Gets the detected patch state for the target.
+        /// </summary>
+        public PackageState State { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectMsiFeature"/>
+    /// </summary>
+    public class DetectMsiFeatureEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectMsiFeatureEventArgs(string packageId, string featureId, FeatureState state, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.FeatureId = featureId;
+            this.State = state;
+        }
+
+        /// <summary>
+        /// Gets the identity of the feature's package detected.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the feature detected.
+        /// </summary>
+        public string FeatureId { get; private set; }
+
+        /// <summary>
+        /// Gets the detected feature state.
+        /// </summary>
+        public FeatureState State { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectPackageComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class DetectPackageCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectPackageCompleteEventArgs(string packageId, int hrStatus, PackageState state, bool cached)
+            : base(hrStatus)
+        {
+            this.PackageId = packageId;
+            this.State = state;
+            this.Cached = cached;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package detected.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the state of the specified package.
+        /// </summary>
+        public PackageState State { get; private set; }
+
+        /// <summary>
+        /// Gets whether any part of the package is cached.
+        /// </summary>
+        public bool Cached { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments used when the detection phase has completed.
+    /// </summary>
+    [Serializable]
+    public class DetectCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectCompleteEventArgs(int hrStatus, bool eligibleForCleanup)
+            : base(hrStatus)
+        {
+            this.EligibleForCleanup = eligibleForCleanup;
+        }
+
+        /// <summary>
+        /// Indicates whether the engine will uninstall the bundle if shutdown without running Apply.
+        /// </summary>
+        public bool EligibleForCleanup { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanBegin"/>
+    /// </summary>
+    [Serializable]
+    public class PlanBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanBeginEventArgs(int packageCount, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageCount = packageCount;
+        }
+
+        /// <summary>
+        /// Gets the number of packages to plan for.
+        /// </summary>
+        public int PackageCount { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanRelatedBundle"/>
+    /// </summary>
+    [Serializable]
+    public class PlanRelatedBundleEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanRelatedBundleEventArgs(string bundleId, RequestState recommendedState, RequestState state, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.BundleId = bundleId;
+            this.RecommendedState = recommendedState;
+            this.State = state;
+        }
+
+        /// <summary>
+        /// Gets the identity of the bundle to plan for.
+        /// </summary>
+        public string BundleId { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended requested state for the bundle.
+        /// </summary>
+        public RequestState RecommendedState { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the requested state for the bundle.
+        /// </summary>
+        public RequestState State { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanRelatedBundleType"/>
+    /// </summary>
+    [Serializable]
+    public class PlanRelatedBundleTypeEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanRelatedBundleTypeEventArgs(string bundleId, RelatedBundlePlanType recommendedType, RelatedBundlePlanType type, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.BundleId = bundleId;
+            this.RecommendedType = recommendedType;
+            this.Type = type;
+        }
+
+        /// <summary>
+        /// Gets the identity of the bundle to plan for.
+        /// </summary>
+        public string BundleId { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended plan type for the bundle.
+        /// </summary>
+        public RelatedBundlePlanType RecommendedType { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the plan type for the bundle.
+        /// </summary>
+        public RelatedBundlePlanType Type { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanPackageBegin"/>
+    /// </summary>
+    [Serializable]
+    public class PlanPackageBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanPackageBeginEventArgs(string packageId, PackageState currentState, bool cached, BOOTSTRAPPER_PACKAGE_CONDITION_RESULT installCondition, BOOTSTRAPPER_PACKAGE_CONDITION_RESULT repairCondition, RequestState recommendedState, BOOTSTRAPPER_CACHE_TYPE recommendedCacheType, RequestState state, BOOTSTRAPPER_CACHE_TYPE cacheType, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.CurrentState = currentState;
+            this.Cached = cached;
+            this.InstallCondition = installCondition;
+            this.RepairCondition = repairCondition;
+            this.RecommendedState = recommendedState;
+            this.RecommendedCacheType = recommendedCacheType;
+            this.State = state;
+            this.CacheType = cacheType;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package to plan for.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the current state of the package.
+        /// </summary>
+        public PackageState CurrentState { get; private set; }
+
+        /// <summary>
+        /// Gets whether any part of the package is cached.
+        /// </summary>
+        public bool Cached { get; private set; }
+
+        /// <summary>
+        /// Gets the evaluated result of the package's install condition.
+        /// </summary>
+        public BOOTSTRAPPER_PACKAGE_CONDITION_RESULT InstallCondition { get; private set; }
+
+        /// <summary>
+        /// Gets the evaluated result of the package's repair condition.
+        /// </summary>
+        public BOOTSTRAPPER_PACKAGE_CONDITION_RESULT RepairCondition { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended requested state for the package.
+        /// </summary>
+        public RequestState RecommendedState { get; private set; }
+
+        /// <summary>
+        /// The authored cache type of the package.
+        /// </summary>
+        public BOOTSTRAPPER_CACHE_TYPE RecommendedCacheType { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the requested state for the package.
+        /// </summary>
+        public RequestState State { get; set; }
+
+        /// <summary>
+        /// Gets or sets the requested cache type for the package.
+        /// </summary>
+        public BOOTSTRAPPER_CACHE_TYPE CacheType { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanCompatibleMsiPackageBegin"/>
+    /// </summary>
+    [Serializable]
+    public class PlanCompatibleMsiPackageBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanCompatibleMsiPackageBeginEventArgs(string packageId, string compatiblePackageId, string compatiblePackageVersion, bool recommendedRemove, bool requestRemove, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.CompatiblePackageId = compatiblePackageId;
+            this.CompatiblePackageVersion = compatiblePackageVersion;
+            this.RecommendedRemove = recommendedRemove;
+            this.RequestRemove = requestRemove;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package that was not detected.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the compatible package detected.
+        /// </summary>
+        public string CompatiblePackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the version of the compatible package detected.
+        /// </summary>
+        public string CompatiblePackageVersion { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended state to use for the compatible package for planning.
+        /// </summary>
+        public bool RecommendedRemove { get; private set; }
+
+        /// <summary>
+        /// Gets or sets whether to uninstall the compatible package.
+        /// </summary>
+        public bool RequestRemove { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanCompatibleMsiPackageComplete"/>
+    /// </summary>
+    [Serializable]
+    public class PlanCompatibleMsiPackageCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanCompatibleMsiPackageCompleteEventArgs(string packageId, string compatiblePackageId, int hrStatus, bool requestedRemove)
+            : base(hrStatus)
+        {
+            this.PackageId = packageId;
+            this.CompatiblePackageId = compatiblePackageId;
+            this.RequestedRemove = requestedRemove;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package planned for.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the compatible package detected.
+        /// </summary>
+        public string CompatiblePackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the requested state of the package.
+        /// </summary>
+        public bool RequestedRemove { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanRollbackBoundary"/>
+    /// </summary>
+    [Serializable]
+    public class PlanRollbackBoundaryEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanRollbackBoundaryEventArgs(string rollbackBoundaryId, bool recommendedTransaction, bool transaction, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.RollbackBoundaryId = rollbackBoundaryId;
+            this.RecommendedTransaction = recommendedTransaction;
+            this.Transaction = transaction;
+        }
+
+        /// <summary>
+        /// Gets the identity of the rollback boundary to plan for.
+        /// </summary>
+        public string RollbackBoundaryId { get; private set; }
+
+        /// <summary>
+        /// Whether or not the rollback boundary was authored to use an MSI transaction.
+        /// </summary>
+        public bool RecommendedTransaction { get; private set; }
+
+        /// <summary>
+        /// Whether or not an MSI transaction will be used in the rollback boundary.
+        /// If <see cref="RecommendedTransaction"/> is false, setting the value to true has no effect.
+        /// If <see cref="RecommendedTransaction"/> is true, setting the value to false will cause the packages inside this rollback boundary to be executed without a wrapping MSI transaction.
+        /// </summary>
+        public bool Transaction { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanPatchTarget"/>
+    /// </summary>
+    [Serializable]
+    public class PlanPatchTargetEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanPatchTargetEventArgs(string packageId, string productCode, RequestState recommendedState, RequestState state, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.ProductCode = productCode;
+            this.RecommendedState = recommendedState;
+            this.State = state;
+        }
+
+        /// <summary>
+        /// Gets the identity of the patch's package.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the product code of the target.
+        /// </summary>
+        public string ProductCode { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended state of the patch to use by planning for the target.
+        /// </summary>
+        public RequestState RecommendedState { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the state of the patch to use by planning for the target.
+        /// </summary>
+        public RequestState State { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanMsiFeature"/>
+    /// </summary>
+    [Serializable]
+    public class PlanMsiFeatureEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanMsiFeatureEventArgs(string packageId, string featureId, FeatureState recommendedState, FeatureState state, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.FeatureId = featureId;
+            this.RecommendedState = recommendedState;
+            this.State = state;
+        }
+
+        /// <summary>
+        /// Gets the identity of the feature's package to plan.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the feature to plan.
+        /// </summary>
+        public string FeatureId { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended feature state to use by planning.
+        /// </summary>
+        public FeatureState RecommendedState { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the feature state to use by planning.
+        /// </summary>
+        public FeatureState State { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanMsiPackage"/>
+    /// </summary>
+    [Serializable]
+    public class PlanMsiPackageEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanMsiPackageEventArgs(string packageId, bool shouldExecute, ActionState action, BOOTSTRAPPER_MSI_FILE_VERSIONING recommendedFileVersioning, bool cancelRecommendation, BURN_MSI_PROPERTY actionMsiProperty, INSTALLUILEVEL uiLevel, bool disableExternalUiHandler, BOOTSTRAPPER_MSI_FILE_VERSIONING fileVersioning)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.ShouldExecute = shouldExecute;
+            this.Action = action;
+            this.RecommendedFileVersioning = recommendedFileVersioning;
+            this.ActionMsiProperty = actionMsiProperty;
+            this.UiLevel = uiLevel;
+            this.DisableExternalUiHandler = disableExternalUiHandler;
+            this.FileVersioning = fileVersioning;
+        }
+
+        /// <summary>
+        /// Gets identity of the package planned for.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets whether the package is planned to execute or roll back.
+        /// </summary>
+        public bool ShouldExecute { get; private set; }
+
+        /// <summary>
+        /// Gets the action planned for the package.
+        /// </summary>
+        public ActionState Action { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended file versioning for the package.
+        /// </summary>
+        public BOOTSTRAPPER_MSI_FILE_VERSIONING RecommendedFileVersioning { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the requested MSI property to add.
+        /// </summary>
+        public BURN_MSI_PROPERTY ActionMsiProperty { get; set; }
+
+        /// <summary>
+        /// Gets or sets the requested internal UI level.
+        /// </summary>
+        public INSTALLUILEVEL UiLevel { get; set; }
+
+        /// <summary>
+        /// Gets or sets whether Burn is requested to set up an external UI handler.
+        /// </summary>
+        public bool DisableExternalUiHandler { get; set; }
+
+        /// <summary>
+        /// Gets or sets the requested file versioning.
+        /// </summary>
+        public BOOTSTRAPPER_MSI_FILE_VERSIONING FileVersioning { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanPackageComplete"/>
+    /// </summary>
+    [Serializable]
+    public class PlanPackageCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanPackageCompleteEventArgs(string packageId, int hrStatus, RequestState requested)
+            : base(hrStatus)
+        {
+            this.PackageId = packageId;
+            this.Requested = requested;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package planned for.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the requested state for the package.
+        /// </summary>
+        public RequestState Requested { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlannedCompatiblePackage"/>
+    /// </summary>
+    [Serializable]
+    public class PlannedCompatiblePackageEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlannedCompatiblePackageEventArgs(string packageId, string compatiblePackageId, bool remove)
+        {
+            this.PackageId = packageId;
+            this.CompatiblePackageId = compatiblePackageId;
+            this.Remove = remove;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package planned for.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the compatible package detected.
+        /// </summary>
+        public string CompatiblePackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the planned state of the package.
+        /// </summary>
+        public bool Remove { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlannedPackage"/>
+    /// </summary>
+    [Serializable]
+    public class PlannedPackageEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlannedPackageEventArgs(string packageId, ActionState execute, ActionState rollback, bool cache, bool uncache)
+        {
+            this.PackageId = packageId;
+            this.Execute = execute;
+            this.Rollback = rollback;
+            this.Cache = cache;
+            this.Uncache = uncache;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package planned for.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the planned execution action.
+        /// </summary>
+        public ActionState Execute { get; private set; }
+
+        /// <summary>
+        /// Gets the planned rollback action.
+        /// </summary>
+        public ActionState Rollback { get; private set; }
+
+        /// <summary>
+        /// Gets whether the package will be cached.
+        /// </summary>
+        public bool Cache { get; private set; }
+
+        /// <summary>
+        /// Gets whether the package will be removed from the package cache.
+        /// </summary>
+        public bool Uncache { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class PlanCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanCompleteEventArgs(int hrStatus)
+            : base(hrStatus)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanForwardCompatibleBundle"/>
+    /// </summary>
+    [Serializable]
+    public class PlanForwardCompatibleBundleEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanForwardCompatibleBundleEventArgs(string bundleId, RelationType relationType, string bundleTag, bool perMachine, string version, bool recommendedIgnoreBundle, bool cancelRecommendation, bool ignoreBundle)
+            : base(cancelRecommendation)
+        {
+            this.BundleId = bundleId;
+            this.RelationType = relationType;
+            this.BundleTag = bundleTag;
+            this.PerMachine = perMachine;
+            this.Version = version;
+            this.RecommendedIgnoreBundle = recommendedIgnoreBundle;
+            this.IgnoreBundle = ignoreBundle;
+        }
+
+        /// <summary>
+        /// Gets the identity of the forward compatible bundle detected.
+        /// </summary>
+        public string BundleId { get; private set; }
+
+        /// <summary>
+        /// Gets the relationship type of the forward compatible bundle.
+        /// </summary>
+        public RelationType RelationType { get; private set; }
+
+        /// <summary>
+        /// Gets the tag of the forward compatible bundle.
+        /// </summary>
+        public string BundleTag { get; private set; }
+
+        /// <summary>
+        /// Gets whether the forward compatible bundle is per machine.
+        /// </summary>
+        public bool PerMachine { get; private set; }
+
+        /// <summary>
+        /// Gets the version of the forward compatible bundle.
+        /// </summary>
+        public string Version { get; private set; }
+
+        /// <summary>
+        /// Gets the recommendation of whether the engine should use the forward compatible bundle.
+        /// </summary>
+        public bool RecommendedIgnoreBundle { get; set; }
+
+        /// <summary>
+        /// Gets or sets whether the engine will use the forward compatible bundle.
+        /// </summary>
+        public bool IgnoreBundle { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ApplyBegin"/>
+    /// </summary>
+    [Serializable]
+    public class ApplyBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ApplyBeginEventArgs(int phaseCount, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PhaseCount = phaseCount;
+        }
+
+        /// <summary>
+        /// Gets the number of phases that the engine will go through in apply.
+        /// There are currently two possible phases: cache and execute.
+        /// </summary>
+        public int PhaseCount { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ElevateBegin"/>
+    /// </summary>
+    [Serializable]
+    public class ElevateBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ElevateBeginEventArgs(bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ElevateComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class ElevateCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ElevateCompleteEventArgs(int hrStatus)
+            : base(hrStatus)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.Progress"/>
+    /// </summary>
+    [Serializable]
+    public class ProgressEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ProgressEventArgs(int progressPercentage, int overallPercentage, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.ProgressPercentage = progressPercentage;
+            this.OverallPercentage = overallPercentage;
+        }
+
+        /// <summary>
+        /// Gets the percentage from 0 to 100 completed for a package.
+        /// </summary>
+        public int ProgressPercentage { get; private set; }
+
+        /// <summary>
+        /// Gets the percentage from 0 to 100 completed for the bundle.
+        /// </summary>
+        public int OverallPercentage { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.Error"/>
+    /// </summary>
+    [Serializable]
+    public class ErrorEventArgs : ResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ErrorEventArgs(ErrorType errorType, string packageId, int errorCode, string errorMessage, int dwUIHint, string[] data, Result recommendation, Result result)
+            : base(recommendation, result)
+        {
+            this.ErrorType = errorType;
+            this.PackageId = packageId;
+            this.ErrorCode = errorCode;
+            this.ErrorMessage = errorMessage;
+            this.UIHint = dwUIHint;
+            this.Data = new ReadOnlyCollection<string>(data ?? new string[] { });
+        }
+
+        /// <summary>
+        /// Gets the type of error that occurred.
+        /// </summary>
+        public ErrorType ErrorType { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the package that yielded the error.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the error code.
+        /// </summary>
+        public int ErrorCode { get; private set; }
+
+        /// <summary>
+        /// Gets the error message.
+        /// </summary>
+        public string ErrorMessage { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended display flags for an error dialog.
+        /// </summary>
+        public int UIHint { get; private set; }
+
+        /// <summary>
+        /// Gets the extended data for the error.
+        /// </summary>
+        public IList<string> Data { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.RegisterBegin"/>
+    /// </summary>
+    [Serializable]
+    public class RegisterBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public RegisterBeginEventArgs(RegistrationType recommendedRegistrationType, bool cancelRecommendation, RegistrationType registrationType)
+            : base(cancelRecommendation)
+        {
+            this.RecommendedRegistrationType = recommendedRegistrationType;
+            this.RegistrationType = registrationType;
+        }
+
+        /// <summary>
+        /// Gets the recommended registration type.
+        /// </summary>
+        public RegistrationType RecommendedRegistrationType { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the registration type.
+        /// </summary>
+        public RegistrationType RegistrationType { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.RegisterComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class RegisterCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public RegisterCompleteEventArgs(int hrStatus)
+            : base(hrStatus)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.UnregisterBegin"/>
+    /// </summary>
+    [Serializable]
+    public class UnregisterBeginEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public UnregisterBeginEventArgs(RegistrationType recommendedRegistrationType, RegistrationType registrationType)
+        {
+            this.RecommendedRegistrationType = recommendedRegistrationType;
+            this.RegistrationType = registrationType;
+        }
+
+        /// <summary>
+        /// Gets the recommended registration type.
+        /// </summary>
+        public RegistrationType RecommendedRegistrationType { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the registration type.
+        /// </summary>
+        public RegistrationType RegistrationType { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.UnregisterComplete"/>
+    /// </summary>
+    [Serializable]
+    public class UnregisterCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public UnregisterCompleteEventArgs(int hrStatus)
+            : base(hrStatus)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CacheBegin"/>
+    /// </summary>
+    [Serializable]
+    public class CacheBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheBeginEventArgs(bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+        }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CacheAcquireBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class CacheAcquireBeginEventArgs : CancellableActionEventArgs<CacheOperation>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheAcquireBeginEventArgs(string packageOrContainerId, string payloadId, string source, string downloadUrl, string payloadContainerId, CacheOperation recommendation, CacheOperation action, bool cancelRecommendation)
+            : base(cancelRecommendation, recommendation, action)
+        {
+            this.PackageOrContainerId = packageOrContainerId;
+            this.PayloadId = payloadId;
+            this.Source = source;
+            this.DownloadUrl = downloadUrl;
+            this.PayloadContainerId = payloadContainerId;
+        }
+
+        /// <summary>
+        /// Gets the identifier of the container or package.
+        /// </summary>
+        public string PackageOrContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identifier of the payload (if acquiring a payload).
+        /// </summary>
+        public string PayloadId { get; private set; }
+
+        /// <summary>
+        /// Gets the source of the container or payload.
+        /// </summary>
+        public string Source { get; private set; }
+
+        /// <summary>
+        /// Gets the optional URL to download container or payload.
+        /// </summary>
+        public string DownloadUrl { get; private set; }
+
+        /// <summary>
+        /// Gets the optional identity of the container that contains the payload being acquired.
+        /// </summary>
+        public string PayloadContainerId { get; private set; }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CacheAcquireProgress"/>.
+    /// </summary>
+    [Serializable]
+    public class CacheAcquireProgressEventArgs : CacheProgressBaseEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheAcquireProgressEventArgs(string packageOrContainerId, string payloadId, long progress, long total, int overallPercentage, bool cancelRecommendation)
+            : base(packageOrContainerId, payloadId, progress, total, overallPercentage, cancelRecommendation)
+        {
+        }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CacheAcquireComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class CacheAcquireCompleteEventArgs : ActionEventArgs<BOOTSTRAPPER_CACHEACQUIRECOMPLETE_ACTION>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheAcquireCompleteEventArgs(string packageOrContainerId, string payloadId, int hrStatus, BOOTSTRAPPER_CACHEACQUIRECOMPLETE_ACTION recommendation, BOOTSTRAPPER_CACHEACQUIRECOMPLETE_ACTION action)
+            : base(hrStatus, recommendation, action)
+        {
+            this.PackageOrContainerId = packageOrContainerId;
+            this.PayloadId = payloadId;
+        }
+
+        /// <summary>
+        /// Gets the identifier of the container or package.
+        /// </summary>
+        public string PackageOrContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identifier of the payload (if acquiring a payload).
+        /// </summary>
+        public string PayloadId { get; private set; }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CacheVerifyBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class CacheVerifyBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheVerifyBeginEventArgs(string packageOrContainerId, string payloadId, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageOrContainerId = packageOrContainerId;
+            this.PayloadId = payloadId;
+        }
+
+        /// <summary>
+        /// Gets the identifier of the container or package.
+        /// </summary>
+        public string PackageOrContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identifier of the payload.
+        /// </summary>
+        public string PayloadId { get; private set; }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CacheVerifyProgress"/>.
+    /// </summary>
+    [Serializable]
+    public class CacheVerifyProgressEventArgs : CacheProgressBaseEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheVerifyProgressEventArgs(string packageOrContainerId, string payloadId, long progress, long total, int overallPercentage, CacheVerifyStep verifyStep, bool cancelRecommendation)
+            : base(packageOrContainerId, payloadId, progress, total, overallPercentage, cancelRecommendation)
+        {
+            this.Step = verifyStep;
+        }
+
+        /// <summary>
+        /// Gets the current verification step.
+        /// </summary>
+        public CacheVerifyStep Step { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CacheVerifyComplete"/>
+    /// </summary>
+    [Serializable]
+    public class CacheVerifyCompleteEventArgs : ActionEventArgs<BOOTSTRAPPER_CACHEVERIFYCOMPLETE_ACTION>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheVerifyCompleteEventArgs(string packageOrContainerId, string payloadId, int hrStatus, BOOTSTRAPPER_CACHEVERIFYCOMPLETE_ACTION recommendation, BOOTSTRAPPER_CACHEVERIFYCOMPLETE_ACTION action)
+            : base(hrStatus, recommendation, action)
+        {
+            this.PackageOrContainerId = packageOrContainerId;
+            this.PayloadId = payloadId;
+        }
+
+        /// <summary>
+        /// Gets the identifier of the container or package.
+        /// </summary>
+        public string PackageOrContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identifier of the payload.
+        /// </summary>
+        public string PayloadId { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CacheComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class CacheCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheCompleteEventArgs(int hrStatus)
+            : base(hrStatus)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ExecuteBegin"/>
+    /// </summary>
+    [Serializable]
+    public class ExecuteBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ExecuteBeginEventArgs(int packageCount, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageCount = packageCount;
+        }
+
+        /// <summary>
+        /// Gets the number of packages to act on.
+        /// </summary>
+        public int PackageCount { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ExecutePackageBegin"/>
+    /// </summary>
+    [Serializable]
+    public class ExecutePackageBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ExecutePackageBeginEventArgs(string packageId, bool shouldExecute, ActionState action, INSTALLUILEVEL uiLevel, bool disableExternalUiHandler, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.ShouldExecute = shouldExecute;
+            this.Action = action;
+            this.UiLevel = uiLevel;
+            this.DisableExternalUiHandler = disableExternalUiHandler;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package to act on.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets whether the package is being executed or rolled back.
+        /// </summary>
+        public bool ShouldExecute { get; private set; }
+
+        /// <summary>
+        /// Gets the action about to be executed.
+        /// </summary>
+        public ActionState Action { get; private set; }
+
+        /// <summary>
+        /// Gets the internal UI level (if this is an MSI or MSP package).
+        /// </summary>
+        public INSTALLUILEVEL UiLevel { get; private set; }
+
+        /// <summary>
+        /// Gets whether Burn will set up an external UI handler (if this is an MSI or MSP package).
+        /// </summary>
+        public bool DisableExternalUiHandler { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ExecutePatchTarget"/>
+    /// </summary>
+    [Serializable]
+    public class ExecutePatchTargetEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ExecutePatchTargetEventArgs(string packageId, string targetProductCode, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.TargetProductCode = targetProductCode;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package to act on.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the product code being targeted.
+        /// </summary>
+        public string TargetProductCode { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ExecuteMsiMessage"/>
+    /// </summary>
+    [Serializable]
+    public class ExecuteMsiMessageEventArgs : ResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ExecuteMsiMessageEventArgs(string packageId, InstallMessage messageType, int dwUIHint, string message, string[] data, Result recommendation, Result result)
+            : base(recommendation, result)
+        {
+            this.PackageId = packageId;
+            this.MessageType = messageType;
+            this.UIHint = dwUIHint;
+            this.Message = message;
+            this.Data = new ReadOnlyCollection<string>(data ?? new string[] { });
+        }
+
+        /// <summary>
+        /// Gets the identity of the package that yielded this message.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the type of this message.
+        /// </summary>
+        public InstallMessage MessageType { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended display flags for this message.
+        /// </summary>
+        public int UIHint { get; private set; }
+
+        /// <summary>
+        /// Gets the message.
+        /// </summary>
+        public string Message { get; private set; }
+
+        /// <summary>
+        /// Gets the extended data for the message.
+        /// </summary>
+        public IList<string> Data { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ExecuteFilesInUse"/>
+    /// </summary>
+    [Serializable]
+    public class ExecuteFilesInUseEventArgs : ResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ExecuteFilesInUseEventArgs(string packageId, string[] files, Result recommendation, FilesInUseType source, Result result)
+            : base(recommendation, result)
+        {
+            this.PackageId = packageId;
+            this.Files = new ReadOnlyCollection<string>(files ?? new string[] { });
+            this.Source = source;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package that yielded the files in use message.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the list of files in use.
+        /// </summary>
+        public IList<string> Files { get; private set; }
+
+        /// <summary>
+        /// Gets the source of the message.
+        /// </summary>
+        public FilesInUseType Source { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ExecutePackageComplete"/>
+    /// </summary>
+    [Serializable]
+    public class ExecutePackageCompleteEventArgs : ActionEventArgs<BOOTSTRAPPER_EXECUTEPACKAGECOMPLETE_ACTION>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ExecutePackageCompleteEventArgs(string packageId, int hrStatus, ApplyRestart restart, BOOTSTRAPPER_EXECUTEPACKAGECOMPLETE_ACTION recommendation, BOOTSTRAPPER_EXECUTEPACKAGECOMPLETE_ACTION action)
+            : base(hrStatus, recommendation, action)
+        {
+            this.PackageId = packageId;
+            this.Restart = restart;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package that was acted on.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the package restart state after being applied.
+        /// </summary>
+        public ApplyRestart Restart { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ExecuteComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class ExecuteCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ExecuteCompleteEventArgs(int hrStatus)
+            : base(hrStatus)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ApplyComplete"/>
+    /// </summary>
+    [Serializable]
+    public class ApplyCompleteEventArgs : ActionEventArgs<BOOTSTRAPPER_APPLYCOMPLETE_ACTION>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ApplyCompleteEventArgs(int hrStatus, ApplyRestart restart, BOOTSTRAPPER_APPLYCOMPLETE_ACTION recommendation, BOOTSTRAPPER_APPLYCOMPLETE_ACTION action)
+            : base(hrStatus, recommendation, action)
+        {
+            this.Restart = restart;
+        }
+
+        /// <summary>
+        /// Gets the apply restart state when complete.
+        /// </summary>
+        public ApplyRestart Restart { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ApplyDowngrade"/>
+    /// </summary>
+    [Serializable]
+    public class ApplyDowngradeEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ApplyDowngradeEventArgs(int hrRecommendation, int hrStatus)
+        {
+            this.Recommendation = hrRecommendation;
+            this.Status = hrStatus;
+        }
+
+        /// <summary>
+        /// Gets the recommended HRESULT.
+        /// </summary>
+        public int Recommendation { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the HRESULT for Apply.
+        /// </summary>
+        public int Status { get; set; }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CacheAcquireResolving"/>.
+    /// </summary>
+    [Serializable]
+    public class CacheAcquireResolvingEventArgs : CancellableActionEventArgs<CacheResolveOperation>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheAcquireResolvingEventArgs(string packageOrContainerId, string payloadId, string[] searchPaths, bool foundLocal, int recommendedSearchPath, string downloadUrl, string payloadContainerId, CacheResolveOperation recommendation, int chosenSearchPath, CacheResolveOperation action, bool cancel)
+            : base(cancel, recommendation, action)
+        {
+            this.PackageOrContainerId = packageOrContainerId;
+            this.PayloadId = payloadId;
+            this.SearchPaths = searchPaths;
+            this.FoundLocal = foundLocal;
+            this.RecommendedSearchPath = recommendedSearchPath;
+            this.DownloadUrl = downloadUrl;
+            this.PayloadContainerId = payloadContainerId;
+            this.ChosenSearchPath = chosenSearchPath;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package or container that is being acquired.
+        /// </summary>
+        public string PackageOrContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the payload that is being acquired.
+        /// </summary>
+        public string PayloadId { get; private set; }
+
+        /// <summary>
+        /// Gets the search paths used for source resolution.
+        /// </summary>
+        public string[] SearchPaths { get; private set; }
+
+        /// <summary>
+        /// Gets whether <see cref="RecommendedSearchPath"/> indicates that a file was found at that search path.
+        /// </summary>
+        public bool FoundLocal { get; private set; }
+
+        /// <summary>
+        /// When <see cref="FoundLocal"/> is true, the index to <see cref="SearchPaths"/> for the recommended local file.
+        /// </summary>
+        public int RecommendedSearchPath { get; private set; }
+
+        /// <summary>
+        /// Gets the optional URL to download container or payload.
+        /// </summary>
+        public string DownloadUrl { get; private set; }
+
+        /// <summary>
+        /// Gets the optional identity of the container that contains the payload being acquired.
+        /// </summary>
+        public string PayloadContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the index to <see cref="SearchPaths"/> to use when <see cref="CancellableActionEventArgs{T}.Action"/> is set to <see cref="CacheOperation.Copy"/>.
+        /// </summary>
+        public int ChosenSearchPath { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CachePackageBegin"/>
+    /// </summary>
+    [Serializable]
+    public class CachePackageBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CachePackageBeginEventArgs(string packageId, int cachePayloads, long packageCacheSize, bool vital, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.CachePayloads = cachePayloads;
+            this.PackageCacheSize = packageCacheSize;
+            this.Vital = vital;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package that is being cached.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets number of payloads to be cached.
+        /// </summary>
+        public long CachePayloads { get; private set; }
+
+        /// <summary>
+        /// Gets the size on disk required by the specific package.
+        /// </summary>
+        public long PackageCacheSize { get; private set; }
+
+        /// <summary>
+        /// If caching a package is not vital, then acquisition will be skipped unless the BA opts in through <see cref="IDefaultBootstrapperApplication.CachePackageNonVitalValidationFailure"/>.
+        /// </summary>
+        public bool Vital { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CachePackageComplete"/>
+    /// </summary>
+    [Serializable]
+    public class CachePackageCompleteEventArgs : ActionEventArgs<BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CachePackageCompleteEventArgs(string packageId, int hrStatus, BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION recommendation, BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION action)
+            : base(hrStatus, recommendation, action)
+        {
+            this.PackageId = packageId;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package that was cached.
+        /// </summary>
+        public string PackageId { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ExecuteProgress"/>
+    /// </summary>
+    [Serializable]
+    public class ExecuteProgressEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ExecuteProgressEventArgs(string packageId, int progressPercentage, int overallPercentage, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.ProgressPercentage = progressPercentage;
+            this.OverallPercentage = overallPercentage;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package that was executed.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the percentage from 0 to 100 of the execution progress for a single payload.
+        /// </summary>
+        public int ProgressPercentage { get; private set; }
+
+        /// <summary>
+        /// Gets the percentage from 0 to 100 of the execution progress for all payloads.
+        /// </summary>
+        public int OverallPercentage { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.LaunchApprovedExeBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class LaunchApprovedExeBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public LaunchApprovedExeBeginEventArgs(bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.LaunchApprovedExeComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class LaunchApprovedExeCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public LaunchApprovedExeCompleteEventArgs(int hrStatus, int processId)
+            : base(hrStatus)
+        {
+            this.ProcessId = processId;
+        }
+
+        /// <summary>
+        /// Gets the ProcessId of the process that was launched.
+        /// This is only valid if the status reports success.
+        /// </summary>
+        public int ProcessId { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.BeginMsiTransactionBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class BeginMsiTransactionBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public BeginMsiTransactionBeginEventArgs(string transactionId, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.TransactionId = transactionId;
+        }
+
+        /// <summary>
+        /// Gets the MSI transaction Id.
+        /// </summary>
+        public string TransactionId { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.BeginMsiTransactionComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class BeginMsiTransactionCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public BeginMsiTransactionCompleteEventArgs(string transactionId, int hrStatus)
+            : base(hrStatus)
+        {
+            this.TransactionId = transactionId;
+        }
+
+        /// <summary>
+        /// Gets the MSI transaction Id.
+        /// </summary>
+        public string TransactionId { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CommitMsiTransactionBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class CommitMsiTransactionBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CommitMsiTransactionBeginEventArgs(string transactionId, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.TransactionId = transactionId;
+        }
+
+        /// <summary>
+        /// Gets the MSI transaction Id.
+        /// </summary>
+        public string TransactionId { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CommitMsiTransactionComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class CommitMsiTransactionCompleteEventArgs : ActionEventArgs<BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CommitMsiTransactionCompleteEventArgs(string transactionId, int hrStatus, ApplyRestart restart, BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION recommendation, BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION action)
+            : base(hrStatus, recommendation, action)
+        {
+            this.TransactionId = transactionId;
+            this.Restart = restart;
+        }
+
+        /// <summary>
+        /// Gets the MSI transaction Id.
+        /// </summary>
+        public string TransactionId { get; private set; }
+
+        /// <summary>
+        /// Gets the package restart state after being applied.
+        /// </summary>
+        public ApplyRestart Restart { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.RollbackMsiTransactionBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class RollbackMsiTransactionBeginEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public RollbackMsiTransactionBeginEventArgs(string transactionId)
+        {
+            this.TransactionId = transactionId;
+        }
+
+        /// <summary>
+        /// Gets the MSI transaction Id.
+        /// </summary>
+        public string TransactionId { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.RollbackMsiTransactionComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class RollbackMsiTransactionCompleteEventArgs : ActionEventArgs<BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public RollbackMsiTransactionCompleteEventArgs(string transactionId, int hrStatus, ApplyRestart restart, BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION recommendation, BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION action)
+            : base(hrStatus, recommendation, action)
+        {
+            this.TransactionId = transactionId;
+            this.Restart = restart;
+        }
+
+        /// <summary>
+        /// Gets the MSI transaction Id.
+        /// </summary>
+        public string TransactionId { get; private set; }
+
+        /// <summary>
+        /// Gets the package restart state after being applied.
+        /// </summary>
+        public ApplyRestart Restart { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PauseAutomaticUpdatesBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class PauseAutomaticUpdatesBeginEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PauseAutomaticUpdatesBeginEventArgs()
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PauseAutomaticUpdatesComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class PauseAutomaticUpdatesCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PauseAutomaticUpdatesCompleteEventArgs(int hrStatus)
+            : base(hrStatus)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.SystemRestorePointBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class SystemRestorePointBeginEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public SystemRestorePointBeginEventArgs()
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.SystemRestorePointComplete"/>.
+    /// </summary>
+    [Serializable]
+    public class SystemRestorePointCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public SystemRestorePointCompleteEventArgs(int hrStatus)
+            : base(hrStatus)
+        {
+        }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CacheContainerOrPayloadVerifyBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class CacheContainerOrPayloadVerifyBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheContainerOrPayloadVerifyBeginEventArgs(string packageOrContainerId, string payloadId, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageOrContainerId = packageOrContainerId;
+            this.PayloadId = payloadId;
+        }
+
+        /// <summary>
+        /// Gets the identifier of the container or package.
+        /// </summary>
+        public string PackageOrContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identifier of the payload.
+        /// </summary>
+        public string PayloadId { get; private set; }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CacheContainerOrPayloadVerifyProgress"/>.
+    /// </summary>
+    [Serializable]
+    public class CacheContainerOrPayloadVerifyProgressEventArgs : CacheProgressBaseEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheContainerOrPayloadVerifyProgressEventArgs(string packageOrContainerId, string payloadId, long progress, long total, int overallPercentage, bool cancelRecommendation)
+            : base(packageOrContainerId, payloadId, progress, total, overallPercentage, cancelRecommendation)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CacheContainerOrPayloadVerifyComplete"/>
+    /// </summary>
+    [Serializable]
+    public class CacheContainerOrPayloadVerifyCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CacheContainerOrPayloadVerifyCompleteEventArgs(string packageOrContainerId, string payloadId, int hrStatus)
+            : base(hrStatus)
+        {
+            this.PackageOrContainerId = packageOrContainerId;
+            this.PayloadId = payloadId;
+        }
+
+        /// <summary>
+        /// Gets the identifier of the container or package.
+        /// </summary>
+        public string PackageOrContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identifier of the payload.
+        /// </summary>
+        public string PayloadId { get; private set; }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CachePayloadExtractBegin"/>.
+    /// </summary>
+    [Serializable]
+    public class CachePayloadExtractBeginEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CachePayloadExtractBeginEventArgs(string containerId, string payloadId, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.ContainerId = containerId;
+            this.PayloadId = payloadId;
+        }
+
+        /// <summary>
+        /// Gets the identifier of the container.
+        /// </summary>
+        public string ContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identifier of the payload.
+        /// </summary>
+        public string PayloadId { get; private set; }
+    }
+
+    /// <summary>
+    /// EventArgs for <see cref="IDefaultBootstrapperApplication.CachePayloadExtractProgress"/>.
+    /// </summary>
+    [Serializable]
+    public class CachePayloadExtractProgressEventArgs : CacheProgressBaseEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CachePayloadExtractProgressEventArgs(string containerId, string payloadId, long progress, long total, int overallPercentage, bool cancelRecommendation)
+            : base(containerId, payloadId, progress, total, overallPercentage, cancelRecommendation)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CachePayloadExtractComplete"/>
+    /// </summary>
+    [Serializable]
+    public class CachePayloadExtractCompleteEventArgs : StatusEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CachePayloadExtractCompleteEventArgs(string containerId, string payloadId, int hrStatus)
+            : base(hrStatus)
+        {
+            this.ContainerId = containerId;
+            this.PayloadId = payloadId;
+        }
+
+        /// <summary>
+        /// Gets the identifier of the container.
+        /// </summary>
+        public string ContainerId { get; private set; }
+
+        /// <summary>
+        /// Gets the identifier of the payload.
+        /// </summary>
+        public string PayloadId { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanRestoreRelatedBundle"/>
+    /// </summary>
+    [Serializable]
+    public class PlanRestoreRelatedBundleEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public PlanRestoreRelatedBundleEventArgs(string bundleId, RequestState recommendedState, RequestState state, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.BundleId = bundleId;
+            this.RecommendedState = recommendedState;
+            this.State = state;
+        }
+
+        /// <summary>
+        /// Gets the identity of the bundle to plan for.
+        /// </summary>
+        public string BundleId { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended requested state for the bundle.
+        /// </summary>
+        public RequestState RecommendedState { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the requested state for the bundle.
+        /// </summary>
+        public RequestState State { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ExecuteProcessCancel"/>
+    /// </summary>
+    [Serializable]
+    public class ExecuteProcessCancelEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public ExecuteProcessCancelEventArgs(string packageId, int processId, BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION recommendation, BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION action)
+        {
+            this.PackageId = packageId;
+            this.ProcessId = processId;
+            this.Recommendation = recommendation;
+            this.Action = action;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the process id.
+        /// </summary>
+        public int ProcessId { get; private set; }
+
+        /// <summary>
+        /// Gets the recommended action from the engine.
+        /// </summary>
+        public BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION Recommendation { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the action to be performed. This is passed back to the engine.
+        /// </summary>
+        public BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION Action { get; set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.DetectRelatedBundlePackage"/>
+    /// </summary>
+    [Serializable]
+    public class DetectRelatedBundlePackageEventArgs : CancellableHResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DetectRelatedBundlePackageEventArgs(string packageId, string productCode, RelationType relationType, bool perMachine, string version, bool cancelRecommendation)
+            : base(cancelRecommendation)
+        {
+            this.PackageId = packageId;
+            this.ProductCode = productCode;
+            this.RelationType = relationType;
+            this.PerMachine = perMachine;
+            this.Version = version;
+        }
+
+        /// <summary>
+        /// Gets the identity of the product's package detected.
+        /// </summary>
+        public string PackageId { get; private set; }
+
+        /// <summary>
+        /// Gets the identity of the related bundle detected.
+        /// </summary>
+        public string ProductCode { get; private set; }
+
+        /// <summary>
+        /// Gets the relationship type of the related bundle.
+        /// </summary>
+        public RelationType RelationType { get; private set; }
+
+        /// <summary>
+        /// Gets whether the detected bundle is per machine.
+        /// </summary>
+        public bool PerMachine { get; private set; }
+
+        /// <summary>
+        /// Gets the version of the related bundle detected.
+        /// </summary>
+        public string Version { get; private set; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.CachePackageNonVitalValidationFailure"/>
+    /// </summary>
+    [Serializable]
+    public class CachePackageNonVitalValidationFailureEventArgs : ActionEventArgs<BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION>
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CachePackageNonVitalValidationFailureEventArgs(string packageId, int hrStatus, BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION recommendation, BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION action)
+            : base(hrStatus, recommendation, action)
+        {
+            this.PackageId = packageId;
+        }
+
+        /// <summary>
+        /// Gets the identity of the package that was being validated.
+        /// </summary>
+        public string PackageId { get; private set; }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperApplication.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperApplication.cs
new file mode 100644
index 00000000..ad7f8dd7
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperApplication.cs
@@ -0,0 +1,2013 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// Allows customization of the bootstrapper application.
+    /// </summary>
+    [ComImport]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    [Guid("53C31D56-49C0-426B-AB06-099D717C67FE")]
+    public interface IBootstrapperApplication
+    {
+        /// <summary>
+        /// Low level method that is called directly from the engine.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int BAProc(
+            int message,
+            IntPtr pvArgs,
+            IntPtr pvResults
+            );
+
+        /// <summary>
+        /// Low level method that is called directly from the engine.
+        /// </summary>
+        void BAProcFallback(
+            int message,
+            IntPtr pvArgs,
+            IntPtr pvResults,
+            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]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnStartup();
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.Shutdown"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnShutdown(ref BOOTSTRAPPER_SHUTDOWN_ACTION action);
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectBegin(
+            [MarshalAs(UnmanagedType.Bool)] bool fCached,
+            [MarshalAs(UnmanagedType.U4)] RegistrationType registrationType,
+            [MarshalAs(UnmanagedType.U4)] int cPackages,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectForwardCompatibleBundle"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectForwardCompatibleBundle(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleId,
+            [MarshalAs(UnmanagedType.U4)] RelationType relationType,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleTag,
+            [MarshalAs(UnmanagedType.Bool)] bool fPerMachine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion,
+            [MarshalAs(UnmanagedType.Bool)] bool fMissingFromCache,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectUpdateBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectUpdateBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzUpdateLocation,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fSkip
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectUpdate"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectUpdate(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzUpdateLocation,
+            [MarshalAs(UnmanagedType.U8)] long dw64Size,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzHash,
+            [MarshalAs(UnmanagedType.U4)] UpdateHashType hashAlgorithm,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzTitle,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzSummary,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzContentType,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzContent,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fStopProcessingUpdates
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectUpdateComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectUpdateComplete(
+            int hrStatus,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fIgnoreError
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectRelatedBundle"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectRelatedBundle(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleId,
+            [MarshalAs(UnmanagedType.U4)] RelationType relationType,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleTag,
+            [MarshalAs(UnmanagedType.Bool)] bool fPerMachine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion,
+            [MarshalAs(UnmanagedType.Bool)] bool fMissingFromCache,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectPackageBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectPackageBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectCompatibleMsiPackage"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectCompatibleMsiPackage(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzCompatiblePackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzCompatiblePackageVersion,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectRelatedMsiPackage"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectRelatedMsiPackage(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzUpgradeCode,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzProductCode,
+            [MarshalAs(UnmanagedType.Bool)] bool fPerMachine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion,
+            [MarshalAs(UnmanagedType.U4)] RelatedOperation operation,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectPatchTarget"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectPatchTarget(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzProductCode,
+            [MarshalAs(UnmanagedType.U4)] PackageState patchState,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectMsiFeature"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectMsiFeature(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzFeatureId,
+            [MarshalAs(UnmanagedType.U4)] FeatureState state,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectPackageComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectPackageComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            int hrStatus,
+            [MarshalAs(UnmanagedType.U4)] PackageState state,
+            [MarshalAs(UnmanagedType.Bool)] bool fCached
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectComplete(
+            int hrStatus,
+            [MarshalAs(UnmanagedType.Bool)] bool fEligibleForCleanup
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanBegin(
+            [MarshalAs(UnmanagedType.U4)] int cPackages,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanRelatedBundle"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanRelatedBundle(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleId,
+            [MarshalAs(UnmanagedType.U4)] RequestState recommendedState,
+            [MarshalAs(UnmanagedType.U4)] ref RequestState pRequestedState,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanRollbackBoundary"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanRollbackBoundary(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzRollbackBoundaryId,
+            [MarshalAs(UnmanagedType.Bool)] bool fRecommendedTransaction,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fTransaction,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanPackageBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanPackageBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.U4)] PackageState state,
+            [MarshalAs(UnmanagedType.Bool)] bool fCached,
+            [MarshalAs(UnmanagedType.U4)] BOOTSTRAPPER_PACKAGE_CONDITION_RESULT installCondition,
+            [MarshalAs(UnmanagedType.U4)] BOOTSTRAPPER_PACKAGE_CONDITION_RESULT repairCondition,
+            [MarshalAs(UnmanagedType.U4)] RequestState recommendedState,
+            [MarshalAs(UnmanagedType.U4)] BOOTSTRAPPER_CACHE_TYPE recommendedCacheType,
+            [MarshalAs(UnmanagedType.U4)] ref RequestState pRequestedState,
+            [MarshalAs(UnmanagedType.U4)] ref BOOTSTRAPPER_CACHE_TYPE pRequestedCacheType,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanCompatibleMsiPackageBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanCompatibleMsiPackageBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzCompatiblePackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzCompatiblePackageVersion,
+            [MarshalAs(UnmanagedType.Bool)] bool fRecommendedRemove,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fRequestRemove,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanCompatibleMsiPackageComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanCompatibleMsiPackageComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzCompatiblePackageId,
+            int hrStatus,
+            [MarshalAs(UnmanagedType.Bool)] bool fRequestedRemove
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanPatchTarget"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanPatchTarget(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzProductCode,
+            [MarshalAs(UnmanagedType.U4)] RequestState recommendedState,
+            [MarshalAs(UnmanagedType.U4)] ref RequestState pRequestedState,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanMsiFeature"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanMsiFeature(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzFeatureId,
+            [MarshalAs(UnmanagedType.U4)] FeatureState recommendedState,
+            [MarshalAs(UnmanagedType.U4)] ref FeatureState pRequestedState,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanMsiPackage"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanMsiPackage(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.Bool)] bool fExecute,
+            [MarshalAs(UnmanagedType.U4)] ActionState action,
+            [MarshalAs(UnmanagedType.U4)] BOOTSTRAPPER_MSI_FILE_VERSIONING recommendedFileVersioning,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel,
+            [MarshalAs(UnmanagedType.U4)] ref BURN_MSI_PROPERTY actionMsiProperty,
+            [MarshalAs(UnmanagedType.U4)] ref INSTALLUILEVEL uiLevel,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fDisableExternalUiHandler,
+            [MarshalAs(UnmanagedType.U4)] ref BOOTSTRAPPER_MSI_FILE_VERSIONING fileVersioning
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanPackageComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanPackageComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            int hrStatus,
+            [MarshalAs(UnmanagedType.U4)] RequestState requested
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlannedCompatiblePackage"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlannedCompatiblePackage(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzCompatiblePackageId,
+            [MarshalAs(UnmanagedType.Bool)] bool fRemove
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlannedPackage"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlannedPackage(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.U4)] ActionState execute,
+            [MarshalAs(UnmanagedType.U4)] ActionState rollback,
+            [MarshalAs(UnmanagedType.Bool)] bool fPlannedCache,
+            [MarshalAs(UnmanagedType.Bool)] bool fPlannedUncache
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanComplete(
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ApplyBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnApplyBegin(
+            [MarshalAs(UnmanagedType.U4)] int dwPhaseCount,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ElevateBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnElevateBegin(
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ElevateComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnElevateComplete(
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.Progress"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnProgress(
+            [MarshalAs(UnmanagedType.U4)] int dwProgressPercentage,
+            [MarshalAs(UnmanagedType.U4)] int dwOverallPercentage,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.Error"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnError(
+            [MarshalAs(UnmanagedType.U4)] ErrorType errorType,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.U4)] int dwCode,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzError,
+            [MarshalAs(UnmanagedType.I4)] int dwUIHint,
+            [MarshalAs(UnmanagedType.U4)] int cData,
+            [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 5, ArraySubType = UnmanagedType.LPWStr), In] string[] rgwzData,
+            [MarshalAs(UnmanagedType.I4)] Result nRecommendation,
+            [MarshalAs(UnmanagedType.I4)] ref Result pResult
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.RegisterBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnRegisterBegin(
+            [MarshalAs(UnmanagedType.I4)] RegistrationType recommendedRegistrationType,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel,
+            [MarshalAs(UnmanagedType.I4)] ref RegistrationType pRegistrationType
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.RegisterComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnRegisterComplete(
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheBegin(
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CachePackageBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCachePackageBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.U4)] int cCachePayloads,
+            [MarshalAs(UnmanagedType.U8)] long dw64PackageCacheSize,
+            [MarshalAs(UnmanagedType.Bool)] bool fVital,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheAcquireBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheAcquireBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzSource,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzDownloadUrl,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadContainerId,
+            [MarshalAs(UnmanagedType.U4)] CacheOperation recommendation,
+            [MarshalAs(UnmanagedType.I4)] ref CacheOperation action,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheAcquireProgress"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheAcquireProgress(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.U8)] long dw64Progress,
+            [MarshalAs(UnmanagedType.U8)] long dw64Total,
+            [MarshalAs(UnmanagedType.U4)] int dwOverallPercentage,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheAcquireResolving"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheAcquireResolving(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3, ArraySubType = UnmanagedType.LPWStr), In] string[] searchPaths,
+            [MarshalAs(UnmanagedType.U4)] int cSearchPaths,
+            [MarshalAs(UnmanagedType.Bool)] bool fFoundLocal,
+            [MarshalAs(UnmanagedType.U4)] int dwRecommendedSearchPath,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzDownloadUrl,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadContainerId,
+            [MarshalAs(UnmanagedType.I4)] CacheResolveOperation recommendation,
+            [MarshalAs(UnmanagedType.U4)] ref int dwChosenSearchPath,
+            [MarshalAs(UnmanagedType.I4)] ref CacheResolveOperation action,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheAcquireComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheAcquireComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            int hrStatus,
+            BOOTSTRAPPER_CACHEACQUIRECOMPLETE_ACTION recommendation,
+            ref BOOTSTRAPPER_CACHEACQUIRECOMPLETE_ACTION pAction
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheVerifyBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheVerifyBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheVerifyProgress"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheVerifyProgress(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.U8)] long dw64Progress,
+            [MarshalAs(UnmanagedType.U8)] long dw64Total,
+            [MarshalAs(UnmanagedType.U4)] int dwOverallPercentage,
+            [MarshalAs(UnmanagedType.I4)] CacheVerifyStep verifyStep,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheVerifyComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheVerifyComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            int hrStatus,
+            BOOTSTRAPPER_CACHEVERIFYCOMPLETE_ACTION recommendation,
+            ref BOOTSTRAPPER_CACHEVERIFYCOMPLETE_ACTION action
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CachePackageComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCachePackageComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            int hrStatus,
+            BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION recommendation,
+            ref BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION action
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheComplete"/>.
+        /// </summary>
+        /// <param name="hrStatus"></param>
+        /// <returns></returns>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheComplete(
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ExecuteBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnExecuteBegin(
+            [MarshalAs(UnmanagedType.U4)] int cExecutingPackages,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ExecutePackageBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnExecutePackageBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.Bool)] bool fExecute,
+            [MarshalAs(UnmanagedType.U4)] ActionState action,
+            [MarshalAs(UnmanagedType.U4)] INSTALLUILEVEL uiLevel,
+            [MarshalAs(UnmanagedType.Bool)] bool fDisableExternalUiHandler,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ExecutePatchTarget"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnExecutePatchTarget(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzTargetProductCode,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ExecuteProgress"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnExecuteProgress(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.U4)] int dwProgressPercentage,
+            [MarshalAs(UnmanagedType.U4)] int dwOverallPercentage,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ExecuteMsiMessage"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnExecuteMsiMessage(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.U4)] InstallMessage messageType,
+            [MarshalAs(UnmanagedType.I4)] int dwUIHint,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzMessage,
+            [MarshalAs(UnmanagedType.U4)] int cData,
+            [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 4, ArraySubType = UnmanagedType.LPWStr), In] string[] rgwzData,
+            [MarshalAs(UnmanagedType.I4)] Result nRecommendation,
+            [MarshalAs(UnmanagedType.I4)] ref Result pResult
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ExecuteFilesInUse"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnExecuteFilesInUse(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.U4)] int cFiles,
+            [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1, ArraySubType = UnmanagedType.LPWStr), In] string[] rgwzFiles,
+            [MarshalAs(UnmanagedType.I4)] Result nRecommendation,
+            [MarshalAs(UnmanagedType.I4)] FilesInUseType source,
+            [MarshalAs(UnmanagedType.I4)] ref Result pResult
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ExecutePackageComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnExecutePackageComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            int hrStatus,
+            [MarshalAs(UnmanagedType.U4)] ApplyRestart restart,
+            [MarshalAs(UnmanagedType.I4)] BOOTSTRAPPER_EXECUTEPACKAGECOMPLETE_ACTION recommendation,
+            [MarshalAs(UnmanagedType.I4)] ref BOOTSTRAPPER_EXECUTEPACKAGECOMPLETE_ACTION pAction
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ExecuteComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnExecuteComplete(
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.UnregisterBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnUnregisterBegin(
+            [MarshalAs(UnmanagedType.I4)] RegistrationType recommendedRegistrationType,
+            [MarshalAs(UnmanagedType.I4)] ref RegistrationType pRegistrationType
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.UnregisterComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnUnregisterComplete(
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ApplyComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnApplyComplete(
+            int hrStatus,
+            [MarshalAs(UnmanagedType.U4)] ApplyRestart restart,
+            [MarshalAs(UnmanagedType.I4)] BOOTSTRAPPER_APPLYCOMPLETE_ACTION recommendation,
+            [MarshalAs(UnmanagedType.I4)] ref BOOTSTRAPPER_APPLYCOMPLETE_ACTION pAction
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.LaunchApprovedExeBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnLaunchApprovedExeBegin(
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.LaunchApprovedExeComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnLaunchApprovedExeComplete(
+            int hrStatus,
+            int processId
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.BeginMsiTransactionBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnBeginMsiTransactionBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzTransactionId,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.BeginMsiTransactionComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnBeginMsiTransactionComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzTransactionId,
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CommitMsiTransactionBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCommitMsiTransactionBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzTransactionId,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CommitMsiTransactionComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCommitMsiTransactionComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzTransactionId,
+            int hrStatus,
+            [MarshalAs(UnmanagedType.U4)] ApplyRestart restart,
+            [MarshalAs(UnmanagedType.I4)] BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION recommendation,
+            [MarshalAs(UnmanagedType.I4)] ref BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION pAction
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.RollbackMsiTransactionBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnRollbackMsiTransactionBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzTransactionId
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.RollbackMsiTransactionComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnRollbackMsiTransactionComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzTransactionId,
+            int hrStatus,
+            [MarshalAs(UnmanagedType.U4)] ApplyRestart restart,
+            [MarshalAs(UnmanagedType.I4)] BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION recommendation,
+            [MarshalAs(UnmanagedType.I4)] ref BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION pAction
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PauseAutomaticUpdatesBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPauseAutomaticUpdatesBegin(
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PauseAutomaticUpdatesComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPauseAutomaticUpdatesComplete(
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.SystemRestorePointBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnSystemRestorePointBegin(
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.SystemRestorePointComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnSystemRestorePointComplete(
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanForwardCompatibleBundle"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanForwardCompatibleBundle(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleId,
+            [MarshalAs(UnmanagedType.U4)] RelationType relationType,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleTag,
+            [MarshalAs(UnmanagedType.Bool)] bool fPerMachine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion,
+            [MarshalAs(UnmanagedType.Bool)] bool fRecommendedIgnoreBundle,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fIgnoreBundle
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheContainerOrPayloadVerifyBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheContainerOrPayloadVerifyBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheContainerOrPayloadVerifyProgress"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheContainerOrPayloadVerifyProgress(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.U8)] long dw64Progress,
+            [MarshalAs(UnmanagedType.U8)] long dw64Total,
+            [MarshalAs(UnmanagedType.U4)] int dwOverallPercentage,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CacheContainerOrPayloadVerifyComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCacheContainerOrPayloadVerifyComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CachePayloadExtractBegin"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCachePayloadExtractBegin(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CachePayloadExtractProgress"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCachePayloadExtractProgress(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.U8)] long dw64Progress,
+            [MarshalAs(UnmanagedType.U8)] long dw64Total,
+            [MarshalAs(UnmanagedType.U4)] int dwOverallPercentage,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CachePayloadExtractComplete"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCachePayloadExtractComplete(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanRestoreRelatedBundle"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanRestoreRelatedBundle(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleId,
+            [MarshalAs(UnmanagedType.U4)] RequestState recommendedState,
+            [MarshalAs(UnmanagedType.U4)] ref RequestState pRequestedState,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.PlanRelatedBundleType"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnPlanRelatedBundleType(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleId,
+            [MarshalAs(UnmanagedType.U4)] RelatedBundlePlanType recommendedType,
+            [MarshalAs(UnmanagedType.U4)] ref RelatedBundlePlanType pRequestedType,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ApplyDowngrade"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnApplyDowngrade(
+            [MarshalAs(UnmanagedType.I4)] int hrRecommended,
+            [MarshalAs(UnmanagedType.I4)] ref int hrStatus
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ExecuteProcessCancel"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnExecuteProcessCancel(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            int processId,
+            [MarshalAs(UnmanagedType.I4)] BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION recommendation,
+            [MarshalAs(UnmanagedType.I4)] ref BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION pAction
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.DetectRelatedBundlePackage"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDetectRelatedBundlePackage(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleId,
+            [MarshalAs(UnmanagedType.U4)] RelationType relationType,
+            [MarshalAs(UnmanagedType.Bool)] bool fPerMachine,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion,
+            [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
+            );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.CachePackageNonVitalValidationFailure"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCachePackageNonVitalValidationFailure(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageId,
+            int hrStatus,
+            BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION recommendation,
+            ref BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION action
+            );
+    }
+
+    /// <summary>
+    /// The display level for the BA.
+    /// </summary>
+    public enum Display
+    {
+        /// <summary>
+        /// Invalid value.
+        /// </summary>
+        Unknown,
+
+        /// <summary>
+        /// The bundle is being run through the Burn protocol by an external application.
+        /// </summary>
+        Embedded,
+
+        /// <summary>
+        /// No UI should be shown.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// The UI should not require any interaction from the user.
+        /// </summary>
+        Passive,
+
+        /// <summary>
+        /// The UI should be fully interactive.
+        /// </summary>
+        Full,
+    }
+
+    /// <summary>
+    /// Messages from Windows Installer (msi.h).
+    /// </summary>
+    public enum InstallMessage
+    {
+        /// <summary>
+        /// premature termination, possibly fatal OOM
+        /// </summary>
+        FatalExit,
+
+        /// <summary>
+        /// formatted error message
+        /// </summary>
+        Error = 0x01000000,
+
+        /// <summary>
+        /// formatted warning message
+        /// </summary>
+        Warning = 0x02000000,
+
+        /// <summary>
+        /// user request message
+        /// </summary>
+        User = 0x03000000,
+
+        /// <summary>
+        /// informative message for log
+        /// </summary>
+        Info = 0x04000000,
+
+        /// <summary>
+        /// list of files in use that need to be replaced
+        /// </summary>
+        FilesInUse = 0x05000000,
+
+        /// <summary>
+        /// request to determine a valid source location
+        /// </summary>
+        ResolveSource = 0x06000000,
+
+        /// <summary>
+        /// insufficient disk space message
+        /// </summary>
+        OutOfDiskSpace = 0x07000000,
+
+        /// <summary>
+        /// start of action: action name &amp; description
+        /// </summary>
+        ActionStart = 0x08000000,
+
+        /// <summary>
+        /// formatted data associated with individual action item
+        /// </summary>
+        ActionData = 0x09000000,
+
+        /// <summary>
+        /// progress gauge info: units so far, total
+        /// </summary>
+        Progress = 0x0a000000,
+
+        /// <summary>
+        /// product info for dialog: language Id, dialog caption
+        /// </summary>
+        CommonData = 0x0b000000,
+
+        /// <summary>
+        /// sent prior to UI initialization, no string data
+        /// </summary>
+        Initialize = 0x0c000000,
+
+        /// <summary>
+        /// sent after UI termination, no string data
+        /// </summary>
+        Terminate = 0x0d000000,
+
+        /// <summary>
+        /// sent prior to display or authored dialog or wizard
+        /// </summary>
+        ShowDialog = 0x0e000000,
+
+        /// <summary>
+        /// log only, to log performance number like action time
+        /// </summary>
+        Performance = 0x0f000000,
+
+        /// <summary>
+        /// the list of apps that the user can request Restart Manager to shut down and restart
+        /// </summary>
+        RMFilesInUse = 0x19000000,
+
+        /// <summary>
+        /// sent prior to server-side install of a product
+        /// </summary>
+        InstallStart = 0x1a000000,
+
+        /// <summary>
+        /// sent after server-side install
+        /// </summary>
+        InstallEnd = 0x1B000000,
+    }
+
+    /// <summary>
+    /// The action to perform when a reboot is necessary.
+    /// </summary>
+    public enum Restart
+    {
+        /// <summary>
+        /// Invalid value.
+        /// </summary>
+        Unknown,
+
+        /// <summary>
+        /// The bundle should never initiate a restart.
+        /// </summary>
+        Never,
+
+        /// <summary>
+        /// The bundle should prompt the user whether to restart.
+        /// </summary>
+        Prompt,
+
+        /// <summary>
+        /// The bundle should restart if necessary.
+        /// </summary>
+        Automatic,
+
+        /// <summary>
+        /// The bundle should always restart when given the option.
+        /// </summary>
+        Always,
+    }
+
+    /// <summary>
+    /// The display name to use when registering in Add/Remove Programs.
+    /// </summary>
+    public enum RegistrationType
+    {
+        /// <summary>
+        /// No registration.
+        /// The engine will ignore None if it recommended InProgress or Full.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// The in-progress display name.
+        /// </summary>
+        InProgress,
+
+        /// <summary>
+        /// The default display name.
+        /// </summary>
+        Full,
+    }
+
+    /// <summary>
+    /// Result codes (based on Dialog Box Command IDs from WinUser.h).
+    /// </summary>
+    public enum Result
+    {
+        /// <summary>
+        /// An error occurred.
+        /// </summary>
+        Error = -1,
+
+        /// <summary>
+        /// Invalid value.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// IDOK
+        /// </summary>
+        Ok,
+
+        /// <summary>
+        /// IDCANCEL
+        /// </summary>
+        Cancel,
+
+        /// <summary>
+        /// IDABORT
+        /// </summary>
+        Abort,
+
+        /// <summary>
+        /// IDRETRY
+        /// </summary>
+        Retry,
+
+        /// <summary>
+        /// IDIGNORE
+        /// </summary>
+        Ignore,
+
+        /// <summary>
+        /// IDYES
+        /// </summary>
+        Yes,
+
+        /// <summary>
+        /// IDNO
+        /// </summary>
+        No,
+
+        /// <summary>
+        /// IDCLOSE
+        /// </summary>
+        Close,
+
+        /// <summary>
+        /// IDHELP
+        /// </summary>
+        Help,
+
+        /// <summary>
+        /// IDTRYAGAIN
+        /// </summary>
+        TryAgain,
+
+        /// <summary>
+        /// IDCONTINUE
+        /// </summary>
+        Continue,
+    }
+
+    /// <summary>
+    /// Describes why a bundle or packaged is being resumed.
+    /// </summary>
+    public enum ResumeType
+    {
+        /// <summary>
+        /// No resume information.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Resume information exists but is invalid.
+        /// </summary>
+        Invalid,
+
+        /// <summary>
+        /// The bundle was re-launched after an unexpected interruption.
+        /// </summary>
+        Interrupted,
+
+        /// <summary>
+        /// The bundle was re-launched after a reboot.
+        /// </summary>
+        Reboot,
+
+        /// <summary>
+        /// The bundle was re-launched after being suspended.
+        /// </summary>
+        Suspend,
+
+        /// <summary>
+        /// The bundle was launched from Add/Remove Programs.
+        /// </summary>
+        Arp,
+    }
+
+    /// <summary>
+    /// Indicates what caused the error.
+    /// </summary>
+    public enum ErrorType
+    {
+        /// <summary>
+        /// The error occurred trying to elevate.
+        /// </summary>
+        Elevate,
+
+        /// <summary>
+        /// The error came from the Windows Installer.
+        /// </summary>
+        WindowsInstaller,
+
+        /// <summary>
+        /// The error came from an EXE Package.
+        /// </summary>
+        ExePackage,
+
+        /// <summary>
+        /// The error came while trying to authenticate with an HTTP server.
+        /// </summary>
+        HttpServerAuthentication,
+
+        /// <summary>
+        /// The error came while trying to authenticate with an HTTP proxy.
+        /// </summary>
+        HttpProxyAuthentication,
+
+        /// <summary>
+        /// The error occurred during apply.
+        /// </summary>
+        Apply,
+    };
+
+    /// <summary>
+    /// Indicates the source of the FilesInUse message.
+    /// </summary>
+    public enum FilesInUseType
+    {
+        /// <summary>
+        /// Generated from INSTALLMESSAGE_FILESINUSE.
+        /// </summary>
+        Msi,
+        /// <summary>
+        /// Generated from INSTALLMESSAGE_RMFILESINUSE.
+        /// </summary>
+        MsiRm,
+        /// <summary>
+        /// Generated from MMIO_CLOSE_APPS.
+        /// </summary>
+        Netfx,
+    }
+
+    /// <summary>
+    /// The calculated operation for the related MSI package.
+    /// </summary>
+    public enum RelatedOperation
+    {
+        /// <summary>
+        /// No relation.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// The related bundle or package will be downgraded.
+        /// </summary>
+        Downgrade,
+
+        /// <summary>
+        /// The related package will be upgraded as a minor revision.
+        /// </summary>
+        MinorUpdate,
+
+        /// <summary>
+        /// The related bundle or package will be upgraded as a major revision.
+        /// </summary>
+        MajorUpgrade,
+
+        /// <summary>
+        /// The related bundle will be removed.
+        /// </summary>
+        Remove,
+
+        /// <summary>
+        /// The related bundle will be installed.
+        /// </summary>
+        Install,
+
+        /// <summary>
+        /// The related bundle will be repaired.
+        /// </summary>
+        Repair,
+    };
+
+    /// <summary>
+    /// The cache operation used to acquire a container or payload.
+    /// </summary>
+    public enum CacheOperation
+    {
+        /// <summary>
+        /// There is no source available.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Copy the payload or container from the chosen local source.
+        /// </summary>
+        Copy,
+
+        /// <summary>
+        /// Download the payload or container using the download URL.
+        /// </summary>
+        Download,
+
+        /// <summary>
+        /// Extract the payload from the container.
+        /// </summary>
+        Extract,
+    }
+
+    /// <summary>
+    /// The source to be used to acquire a container or payload.
+    /// </summary>
+    public enum CacheResolveOperation
+    {
+        /// <summary>
+        /// There is no source available.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Copy the payload or container from the chosen local source.
+        /// </summary>
+        Local,
+
+        /// <summary>
+        /// Download the payload or container from the download URL.
+        /// </summary>
+        Download,
+
+        /// <summary>
+        /// Extract the payload from the container.
+        /// </summary>
+        Container,
+
+        /// <summary>
+        /// Look again for the payload or container locally.
+        /// </summary>
+        Retry,
+    }
+
+    /// <summary>
+    /// The current step when verifying a container or payload.
+    /// </summary>
+    public enum CacheVerifyStep
+    {
+        /// <summary>
+        /// Copying or moving the file from the working path to the unverified path.
+        /// Not used during Layout.
+        /// </summary>
+        Stage,
+        /// <summary>
+        /// Hashing the file.
+        /// </summary>
+        Hash,
+        /// <summary>
+        /// Copying or moving the file to the final location.
+        /// </summary>
+        Finalize,
+    }
+
+    /// <summary>
+    /// The restart state after a package or all packages were applied.
+    /// </summary>
+    public enum ApplyRestart
+    {
+        /// <summary>
+        /// Package or chain does not require a restart.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Package or chain requires a restart but it has not been initiated yet.
+        /// </summary>
+        RestartRequired,
+
+        /// <summary>
+        /// Package or chain has already initiated the restart.
+        /// </summary>
+        RestartInitiated
+    }
+
+    /// <summary>
+    /// The relation type for related bundles.
+    /// </summary>
+    public enum RelationType
+    {
+        /// <summary>
+        /// No relation.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// The related bundle is detected by the running bundle.
+        /// This relationship is reversed for <see cref="IBootstrapperCommand.Relation" />
+        /// </summary>
+        Detect,
+
+        /// <summary>
+        /// The related bundle shares an upgrade code with the running bundle.
+        /// This relationship is reversed for <see cref="IBootstrapperCommand.Relation" />
+        /// </summary>
+        Upgrade,
+
+        /// <summary>
+        /// The related bundle is an add-on for the running bundle.
+        /// This relationship is reversed for <see cref="IBootstrapperCommand.Relation" />
+        /// </summary>
+        Addon,
+
+        /// <summary>
+        /// The related bundle is a patch for the running bundle.
+        /// This relationship is reversed for <see cref="IBootstrapperCommand.Relation" />
+        /// </summary>
+        Patch,
+
+        /// <summary>
+        /// The running bundle is an add-on for the related bundle.
+        /// This relationship is reversed for <see cref="IBootstrapperCommand.Relation" />
+        /// </summary>
+        DependentAddon,
+
+        /// <summary>
+        /// The running bundle is a patch for the related bundle.
+        /// This relationship is reversed for <see cref="IBootstrapperCommand.Relation" />
+        /// </summary>
+        DependentPatch,
+
+        /// <summary>
+        /// The related bundle is a newer version of the running bundle.
+        /// This relationship is reversed for <see cref="IBootstrapperCommand.Relation" />
+        /// </summary>
+        Update,
+
+        /// <summary>
+        /// The related bundle is in the running bundle's chain.
+        /// This relationship is reversed for <see cref="IBootstrapperCommand.Relation" />
+        /// </summary>
+        ChainPackage,
+    }
+
+    /// <summary>
+    /// The planned relation type for related bundles.
+    /// </summary>
+    public enum RelatedBundlePlanType
+    {
+        /// <summary>
+        /// Don't execute the related bundle.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// The running bundle is a downgrade for the related bundle.
+        /// </summary>
+        Downgrade,
+
+        /// <summary>
+        /// The running bundle is an upgrade for the related bundle.
+        /// </summary>
+        Upgrade,
+
+        /// <summary>
+        /// The related bundle is an add-on of the running bundle.
+        /// </summary>
+        Addon,
+
+        /// <summary>
+        /// The related bundle is a patch for the running bundle.
+        /// </summary>
+        Patch,
+
+        /// <summary>
+        /// The running bundle is an add-on for the related bundle.
+        /// </summary>
+        DependentAddon,
+
+        /// <summary>
+        /// The running bundle is a patch for the related bundle.
+        /// </summary>
+        DependentPatch,
+    }
+
+    /// <summary>
+    /// One or more reasons why the application is requested to be closed or is being closed.
+    /// </summary>
+    [Flags]
+    public enum EndSessionReasons
+    {
+        /// <summary>
+        /// The system is shutting down or restarting (it is not possible to determine which event is occurring).
+        /// </summary>
+        Unknown,
+
+        /// <summary>
+        /// The application is using a file that must be replaced, the system is being serviced, or system resources are exhausted.
+        /// </summary>
+        CloseApplication,
+
+        /// <summary>
+        /// The application is forced to shut down.
+        /// </summary>
+        Critical = 0x40000000,
+
+        /// <summary>
+        /// The user is logging off.
+        /// </summary>
+        Logoff = unchecked((int)0x80000000)
+    }
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.ApplyComplete"/>.
+    /// </summary>
+    public enum BOOTSTRAPPER_APPLYCOMPLETE_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine to not take any special action.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Instructs the engine to restart.
+        /// The engine will not launch again after the machine is rebooted.
+        /// Ignored if reboot was already initiated by <see cref="IDefaultBootstrapperApplication.ExecutePackageComplete"/>.
+        /// </summary>
+        Restart,
+    }
+
+    /// <summary>
+    /// The cache strategy to be used for the package.
+    /// </summary>
+    public enum BOOTSTRAPPER_CACHE_TYPE
+    {
+        /// <summary>
+        /// The package will be cached in order to securely run the package, but will always be cleaned from the cache at the end.
+        /// </summary>
+        Remove,
+
+        /// <summary>
+        /// The package will be cached in order to run the package, and then kept in the cache until the package is uninstalled.
+        /// </summary>
+        Keep,
+
+        /// <summary>
+        /// The package will always be cached and stay in the cache, unless the package and bundle are both being uninstalled.
+        /// </summary>
+        Force,
+    }
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.CacheAcquireComplete"/>.
+    /// </summary>
+    public enum BOOTSTRAPPER_CACHEACQUIRECOMPLETE_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine to not take any special action.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Instructs the engine to try the acquisition of the payload again.
+        /// Ignored if hrStatus is a success.
+        /// </summary>
+        Retry,
+    }
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.CachePackageComplete"/>.
+    /// </summary>
+    public enum BOOTSTRAPPER_CACHEPACKAGECOMPLETE_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine to not take any special action.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Instructs the engine to ignore non-vital package failures and continue with the caching.
+        /// Ignored if hrStatus is a success or the package is vital.
+        /// </summary>
+        Ignore,
+
+        /// <summary>
+        /// Instructs the engine to try the acquisition and verification of the package again.
+        /// Ignored if hrStatus is a success.
+        /// </summary>
+        Retry,
+    }
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.CachePackageNonVitalValidationFailure"/>
+    /// </summary>
+    public enum BOOTSTRAPPER_CACHEPACKAGENONVITALVALIDATIONFAILURE_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine to not take any special action.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Instructs the engine to try to acquire the package so execution can use it.
+        /// Most of the time this is used for installing the package during rollback.
+        /// </summary>
+        Acquire,
+    }
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.CacheVerifyComplete"/>.
+    /// </summary>
+    public enum BOOTSTRAPPER_CACHEVERIFYCOMPLETE_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine to not take any special action.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Ignored if hrStatus is a success.
+        /// </summary>
+        RetryVerification,
+
+        /// <summary>
+        /// Ignored if hrStatus is a success.
+        /// </summary>
+        RetryAcquisition,
+    }
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.ExecutePackageComplete"/>.
+    /// </summary>
+    public enum BOOTSTRAPPER_EXECUTEPACKAGECOMPLETE_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine to not take any special action.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Instructs the engine to ignore non-vital package failures and continue with the install.
+        /// Ignored if hrStatus is a success or the package is vital.
+        /// </summary>
+        Ignore,
+
+        /// <summary>
+        /// Instructs the engine to try the execution of the package again.
+        /// Ignored if hrStatus is a success.
+        /// </summary>
+        Retry,
+
+        /// <summary>
+        /// Instructs the engine to stop processing the chain and restart.
+        /// The engine will launch again after the machine is restarted.
+        /// </summary>
+        Restart,
+
+        /// <summary>
+        /// Instructs the engine to stop processing the chain and suspend the current state.
+        /// </summary>
+        Suspend,
+    }
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.CommitMsiTransactionComplete"/> and <see cref="IDefaultBootstrapperApplication.RollbackMsiTransactionComplete"/>.
+    /// </summary>
+    public enum BOOTSTRAPPER_EXECUTEMSITRANSACTIONCOMPLETE_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine to not take any special action.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Instructs the engine to stop processing the chain and restart.
+        /// The engine will launch again after the machine is restarted.
+        /// </summary>
+        Restart,
+    };
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.ExecuteProcessCancel"/>.
+    /// </summary>
+    public enum BOOTSTRAPPER_EXECUTEPROCESSCANCEL_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine to stop waiting for the process to exit.
+        /// The package is immediately considered to have failed with ERROR_INSTALL_USEREXIT.
+        /// The engine will never rollback the package.
+        /// </summary>
+        Abandon,
+
+        /// <summary>
+        /// Instructs the engine to wait for the process to exit.
+        /// Once the process has exited, the package is considered to have failed with ERROR_INSTALL_USEREXIT.
+        /// This allows the engine to rollback the package if necessary.
+        /// </summary>
+        Wait,
+    }
+
+    /// <summary>
+    /// The result of evaluating a condition from a package.
+    /// </summary>
+    public enum BOOTSTRAPPER_PACKAGE_CONDITION_RESULT
+    {
+        /// <summary>
+        /// No condition was authored.
+        /// </summary>
+        Default,
+
+        /// <summary>
+        /// Evaluated to false.
+        /// </summary>
+        False,
+
+        /// <summary>
+        /// Evaluated to true.
+        /// </summary>
+        True,
+    }
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.CacheAcquireResolving"/>.
+    /// </summary>
+    public enum BOOTSTRAPPER_RESOLVESOURCE_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine that the source can't be found.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Instructs the engine to try the local source again.
+        /// </summary>
+        Retry,
+
+        /// <summary>
+        /// Instructs the engine to try the download source.
+        /// </summary>
+        Download,
+    }
+
+    /// <summary>
+    /// The available actions for <see cref="IDefaultBootstrapperApplication.Shutdown"/>.
+    /// </summary>
+    public enum BOOTSTRAPPER_SHUTDOWN_ACTION
+    {
+        /// <summary>
+        /// Instructs the engine to not take any special action.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Instructs the engine to restart.
+        /// The engine will not launch again after the machine is rebooted.
+        /// Ignored if reboot was already initiated by <see cref="IDefaultBootstrapperApplication.ExecutePackageComplete"/>.
+        /// </summary>
+        Restart,
+
+        /// <summary>
+        /// Instructs the engine to unload the bootstrapper application and
+        /// restart the engine which will load the bootstrapper application again.
+        /// Typically used to switch from a native bootstrapper application to a managed one.
+        /// </summary>
+        ReloadBootstrapper,
+
+        /// <summary>
+        /// Opts out of the engine behavior of trying to uninstall itself when no non-permanent packages are installed.
+        /// </summary>
+        SkipCleanup,
+    }
+
+    /// <summary>
+    /// The file versioning options for REINSTALLMODE, see https://docs.microsoft.com/en-us/windows/win32/msi/reinstallmode.
+    /// </summary>
+    public enum BOOTSTRAPPER_MSI_FILE_VERSIONING
+    {
+        /// <summary>
+        /// o
+        /// </summary>
+        Older,
+        /// <summary>
+        /// e
+        /// </summary>
+        Equal,
+        /// <summary>
+        /// a
+        /// </summary>
+        All,
+    }
+
+    /// <summary>
+    /// The property Burn will add so the MSI can know the planned action for the package.
+    /// </summary>
+    public enum BURN_MSI_PROPERTY
+    {
+        /// <summary>
+        /// No property will be added.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Add BURNMSIINSTALL=1
+        /// </summary>
+        Install,
+
+        /// <summary>
+        /// Add BURNMSIMODFIY=1
+        /// </summary>
+        Modify,
+
+        /// <summary>
+        /// Add BURNMSIREPAIR=1
+        /// </summary>
+        Repair,
+
+        /// <summary>
+        /// Add BURNMSIUNINSTALL=1
+        /// </summary>
+        Uninstall,
+    }
+
+    /// <summary>
+    /// From msi.h
+    /// https://docs.microsoft.com/en-us/windows/win32/api/msi/nf-msi-msisetinternalui
+    /// </summary>
+    [Flags]
+    public enum INSTALLUILEVEL
+    {
+        /// <summary>
+        /// UI level is unchanged
+        /// </summary>
+        NoChange = 0,
+
+        /// <summary>
+        /// default UI is used
+        /// </summary>
+        Default = 1,
+
+        /// <summary>
+        /// completely silent installation
+        /// </summary>
+        None = 2,
+
+        /// <summary>
+        /// simple progress and error handling
+        /// </summary>
+        Basic = 3,
+
+        /// <summary>
+        /// authored UI, wizard dialogs suppressed
+        /// </summary>
+        Reduced = 4,
+
+        /// <summary>
+        /// authored UI with wizards, progress, errors
+        /// </summary>
+        Full = 5,
+
+        /// <summary>
+        /// display success/failure dialog at end of install
+        /// </summary>
+        EndDialog = 0x80,
+
+        /// <summary>
+        /// display only progress dialog
+        /// </summary>
+        ProgressOnly = 0x40,
+
+        /// <summary>
+        /// do not display the cancel button in basic UI
+        /// </summary>
+        HideCancel = 0x20,
+
+        /// <summary>
+        /// force display of source resolution even if quiet
+        /// </summary>
+        SourceResOnly = 0x100,
+
+        /// <summary>
+        /// show UAC prompt even if quiet
+        /// Can only be used if on Windows Installer 5.0 or later
+        /// </summary>
+        UacOnly = 0x200,
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperApplicationData.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperApplicationData.cs
new file mode 100644
index 00000000..d26d89c1
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperApplicationData.cs
@@ -0,0 +1,22 @@
+// 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.BootstrapperApplicationApi
+{
+    using System.IO;
+
+    /// <summary>
+    /// Interface for BootstrapperApplicationData.xml.
+    /// </summary>
+    public interface IBootstrapperApplicationData
+    {
+        /// <summary>
+        /// The BootstrapperApplicationData.xml file.
+        /// </summary>
+        FileInfo BADataFile { get; }
+
+        /// <summary>
+        /// The BA manifest.
+        /// </summary>
+        IBundleInfo Bundle { get; }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperApplicationFactory.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperApplicationFactory.cs
new file mode 100644
index 00000000..ac90c0b7
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperApplicationFactory.cs
@@ -0,0 +1,22 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.CodeDom.Compiler;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// 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 interface IBootstrapperApplicationFactory
+    {
+        /// <summary>
+        /// This is no longer used.
+        /// </summary>
+        /// <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.BootstrapperApplicationApi/IBootstrapperCommand.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperCommand.cs
new file mode 100644
index 00000000..a1f8bfe0
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperCommand.cs
@@ -0,0 +1,79 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+
+    /// <summary>
+    /// Command information passed from the engine for the BA to perform.
+    /// </summary>
+    public interface IBootstrapperCommand
+    {
+        /// <summary>
+        /// Gets the action for the BA to perform.
+        /// </summary>
+        LaunchAction Action { get; }
+
+        /// <summary>
+        /// Gets the display level for the BA.
+        /// </summary>
+        Display Display { get; }
+
+        /// <summary>
+        /// Gets the command line arguments.
+        /// </summary>
+        /// <returns>
+        /// Command line arguments not handled by the engine.
+        /// </returns>
+        string CommandLine { get; }
+
+        /// <summary>
+        /// Hint for the initial visibility of the window.
+        /// </summary>
+        int CmdShow { get; }
+
+        /// <summary>
+        /// Gets the method of how the engine was resumed from a previous installation step.
+        /// </summary>
+        ResumeType Resume { get; }
+
+        /// <summary>
+        /// Gets the handle to the splash screen window. If no splash screen was displayed this value will be IntPtr.Zero.
+        /// </summary>
+        IntPtr SplashScreen { get; }
+
+        /// <summary>
+        /// If this was run from a related bundle, specifies the relation type.
+        /// </summary>
+        RelationType Relation { get; }
+
+        /// <summary>
+        /// If this was run from a backward compatible bundle.
+        /// </summary>
+        bool Passthrough { get; }
+
+        /// <summary>
+        /// Gets layout directory.
+        /// </summary>
+        string LayoutDirectory { get; }
+
+        /// <summary>
+        /// Gets bootstrapper working folder.
+        /// </summary>
+        string BootstrapperWorkingFolder { get; }
+
+        /// <summary>
+        /// Gets path to BootstrapperApplicationData.xml.
+        /// </summary>
+        string BootstrapperApplicationDataPath { get; }
+
+        /// <summary>
+        /// Parses the command line arguments into an <see cref="IMbaCommand"/>.
+        /// </summary>
+        /// <returns>
+        /// The parsed information.
+        /// </returns>
+        /// <exception type="Win32Exception">The command line could not be parsed.</exception>
+        IMbaCommand ParseCommandLine();
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperEngine.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperEngine.cs
new file mode 100644
index 00000000..1e91cd31
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBootstrapperEngine.cs
@@ -0,0 +1,501 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.CodeDom.Compiler;
+    using System.Runtime.InteropServices;
+    using System.Text;
+
+    /// <summary>
+    /// Allows calls into the bootstrapper engine.
+    /// </summary>
+    [ComImport]
+    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+    [Guid("6480D616-27A0-44D7-905B-81512C29C2FB")]
+    [GeneratedCodeAttribute("WixToolset.Bootstrapper.InteropCodeGenerator", "1.0.0.0")]
+    public interface IBootstrapperEngine
+    {
+        /// <summary>
+        /// See <see cref="IEngine.PackageCount"/>.
+        /// </summary>
+        void GetPackageCount(
+            [MarshalAs(UnmanagedType.U4)] out int pcPackages
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.GetVariableNumeric(string)"/>.
+        /// </summary>
+        [PreserveSig]
+        int GetVariableNumeric(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+            out long pllValue
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.GetVariableString(string)"/>.
+        /// </summary>
+        [PreserveSig]
+        int GetVariableString(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+                                              IntPtr wzValue,
+                                          ref IntPtr pcchValue
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.GetVariableVersion(string)"/>.
+        /// </summary>
+        [PreserveSig]
+        int GetVariableVersion(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+                                              IntPtr wzValue,
+                                          ref IntPtr pcchValue
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.FormatString(string)"/>.
+        /// </summary>
+        [PreserveSig]
+        int FormatString(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzIn,
+            [MarshalAs(UnmanagedType.LPWStr), Out] StringBuilder wzOut,
+            ref IntPtr pcchOut
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.EscapeString(string)"/>.
+        /// </summary>
+        [PreserveSig]
+        int EscapeString(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzIn,
+            [MarshalAs(UnmanagedType.LPWStr), Out] StringBuilder wzOut,
+            ref IntPtr pcchOut
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.EvaluateCondition(string)"/>.
+        /// </summary>
+        void EvaluateCondition(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzCondition,
+            [MarshalAs(UnmanagedType.Bool)] out bool pf
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.Log(LogLevel, string)"/>.
+        /// </summary>
+        void Log(
+            [MarshalAs(UnmanagedType.U4)] LogLevel level,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzMessage
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.SendEmbeddedError(int, string, int)"/>.
+        /// </summary>
+        void SendEmbeddedError(
+            [MarshalAs(UnmanagedType.U4)] int dwErrorCode,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzMessage,
+            [MarshalAs(UnmanagedType.U4)] int dwUIHint,
+            [MarshalAs(UnmanagedType.I4)] out int pnResult
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.SendEmbeddedProgress(int, int)"/>.
+        /// </summary>
+        void SendEmbeddedProgress(
+            [MarshalAs(UnmanagedType.U4)] int dwProgressPercentage,
+            [MarshalAs(UnmanagedType.U4)] int dwOverallProgressPercentage,
+            [MarshalAs(UnmanagedType.I4)] out int pnResult
+            );
+
+        /// <summary>
+        /// 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 wzUpdatePackageId
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.SetLocalSource(string, string, string)"/>.
+        /// </summary>
+        void SetLocalSource(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPath
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.SetDownloadSource(string, string, string, string, string)"/>.
+        /// </summary>
+        void SetDownloadSource(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPackageOrContainerId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPayloadId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzUrl,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzUser,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzPassword
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.SetVariableNumeric(string, long)"/>.
+        /// </summary>
+        void SetVariableNumeric(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+            long llValue
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.SetVariableString(string, string, bool)"/>.
+        /// </summary>
+        void SetVariableString(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+                                              IntPtr wzValue,
+            [MarshalAs(UnmanagedType.Bool)]   bool fFormatted
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.SetVariableVersion(string, string)"/>.
+        /// </summary>
+        void SetVariableVersion(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+                                              IntPtr wzValue
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.CloseSplashScreen"/>.
+        /// </summary>
+        void CloseSplashScreen();
+
+        /// <summary>
+        /// See <see cref="IEngine.Detect(IntPtr)"/>.
+        /// </summary>
+        void Detect(
+            IntPtr hwndParent
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.Plan(LaunchAction)"/>.
+        /// </summary>
+        void Plan(
+            [MarshalAs(UnmanagedType.U4)] LaunchAction action
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.Elevate(IntPtr)"/>.
+        /// </summary>
+        [PreserveSig]
+        int Elevate(
+            IntPtr hwndParent
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.Apply(IntPtr)"/>.
+        /// </summary>
+        void Apply(
+            IntPtr hwndParent
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.Quit(int)"/>.
+        /// </summary>
+        void Quit(
+            [MarshalAs(UnmanagedType.U4)] int dwExitCode
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.LaunchApprovedExe(IntPtr, string, string, int)"/>.
+        /// </summary>
+        void LaunchApprovedExe(
+            IntPtr hwndParent,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzApprovedExeForElevationId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzArguments,
+            [MarshalAs(UnmanagedType.U4)] int dwWaitForInputIdleTimeout
+            );
+
+        /// <summary>
+        /// Sets the URL to the update feed.
+        /// </summary>
+        void SetUpdateSource(
+            [MarshalAs(UnmanagedType.LPWStr)] string url
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.CompareVersions(string, string)"/>.
+        /// </summary>
+        void CompareVersions(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion1,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion2,
+            [MarshalAs(UnmanagedType.I4)] out int pnResult
+            );
+
+        /// <summary>
+        /// See <see cref="IEngine.GetRelatedBundleVariable(string, string)"/>.
+        /// </summary>
+        [PreserveSig]
+        int GetRelatedBundleVariable(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzBundleId,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVariable,
+                                              IntPtr wzValue,
+                                          ref IntPtr pcchValue
+            );
+    }
+
+    /// <summary>
+    /// The installation action for the bundle or current package.
+    /// </summary>
+    public enum ActionState
+    {
+        /// <summary>
+        /// No action.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Uninstall action.
+        /// </summary>
+        Uninstall,
+
+        /// <summary>
+        /// Install action.
+        /// </summary>
+        Install,
+
+        /// <summary>
+        /// Modify action.
+        /// </summary>
+        Modify,
+
+        /// <summary>
+        /// Repair action.
+        /// </summary>
+        Repair,
+
+        /// <summary>
+        /// Minor upgrade action.
+        /// </summary>
+        MinorUpgrade,
+    }
+
+    /// <summary>
+    /// The action for the bundle to perform.
+    /// </summary>
+    public enum LaunchAction
+    {
+        /// <summary>
+        /// Invalid action.
+        /// </summary>
+        Unknown,
+
+        /// <summary>
+        /// Provide help information.
+        /// </summary>
+        Help,
+
+        /// <summary>
+        /// Layout the bundle on disk, normally to prepare for offline installation.
+        /// </summary>
+        Layout,
+
+        /// <summary>
+        /// Same as Uninstall, except it will always remove itself from the package cache and Add/Remove Programs.
+        /// This should only be used to remove corrupt bundles since it might not properly clean up its packages.
+        /// </summary>
+        UnsafeUninstall,
+
+        /// <summary>
+        /// Uninstall the bundle.
+        /// </summary>
+        Uninstall,
+
+        /// <summary>
+        /// Cache the bundle and its packages.
+        /// </summary>
+        Cache,
+
+        /// <summary>
+        /// Install the bundle.
+        /// </summary>
+        Install,
+
+        /// <summary>
+        /// Modify the bundle.
+        /// </summary>
+        Modify,
+
+        /// <summary>
+        /// Repair the bundle
+        /// </summary>
+        Repair,
+
+        /// <summary>
+        /// 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, string)"/> as an embedded bundle.
+        /// </summary>
+        UpdateReplaceEmbedded,
+    }
+
+    /// <summary>
+    /// The message log level.
+    /// </summary>
+    public enum LogLevel
+    {
+        /// <summary>
+        /// No logging level (generic).
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// User messages.
+        /// </summary>
+        Standard,
+
+        /// <summary>
+        /// Verbose messages.
+        /// </summary>
+        Verbose,
+
+        /// <summary>
+        /// Messages for debugging.
+        /// </summary>
+        Debug,
+
+        /// <summary>
+        /// Error messages.
+        /// </summary>
+        Error,
+    }
+
+    /// <summary>
+    /// Type of hash used for update bundle.
+    /// </summary>
+    public enum UpdateHashType
+    {
+        /// <summary>
+        /// No hash provided.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// SHA-512 based hash provided.
+        /// </summary>
+        Sha512,
+    }
+
+    /// <summary>
+    /// Describes the state of an installation package.
+    /// </summary>
+    public enum PackageState
+    {
+        /// <summary>
+        /// Invalid state.
+        /// </summary>
+        Unknown,
+
+        /// <summary>
+        /// The package is not on the machine (except possibly MspPackage) and should not be installed.
+        /// </summary>
+        Obsolete,
+
+        /// <summary>
+        /// The package is not installed.
+        /// </summary>
+        Absent,
+
+        /// <summary>
+        /// The package is installed.
+        /// </summary>
+        Present,
+
+        /// <summary>
+        /// The package is on the machine but not active, so only uninstall operations are allowed.
+        /// </summary>
+        Superseded,
+
+        /// <summary>
+        /// This value is no longer used. See the DetectPackageCompleteEventArgs.Cached value instead.
+        /// </summary>
+        [Obsolete("Use DetectPackageCompleteEventArgs.Cached instead.")]
+        Cached = Present,
+    }
+
+    /// <summary>
+    /// Indicates the state desired for an installation package.
+    /// </summary>
+    public enum RequestState
+    {
+        /// <summary>
+        /// No change requested.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// As long as there are no dependents, the package will be uninstalled.
+        /// There are some packages that can't be uninstalled, such as an ExePackage without an UninstallCommand.
+        /// </summary>
+        ForceAbsent,
+
+        /// <summary>
+        /// Request the package to not be installed on the machine.
+        /// </summary>
+        Absent,
+
+        /// <summary>
+        /// Request the package to be cached and not be installed on the machine.
+        /// </summary>
+        Cache,
+
+        /// <summary>
+        /// Request the package to be installed on the machine.
+        /// </summary>
+        Present,
+
+        /// <summary>
+        /// Force the bundle to install the package.
+        /// </summary>
+        ForcePresent,
+
+        /// <summary>
+        /// Request the package to be repaired.
+        /// </summary>
+        Repair,
+    }
+
+    /// <summary>
+    /// Indicates the state of a feature.
+    /// See https://learn.microsoft.com/en-us/windows/win32/api/msi/nf-msi-msiqueryfeaturestatew.
+    /// </summary>
+    public enum FeatureState
+    {
+        /// <summary>
+        /// Invalid state.
+        /// </summary>
+        Unknown,
+
+        /// <summary>
+        /// INSTALLSTATE_ABSENT
+        /// </summary>
+        Absent,
+
+        /// <summary>
+        /// INSTALLSTATE_ADVERTISED
+        /// </summary>
+        Advertised,
+
+        /// <summary>
+        /// INSTALLSTATE_LOCAL
+        /// </summary>
+        Local,
+
+        /// <summary>
+        /// INSTALLSTATE_SOURCE
+        /// </summary>
+        Source,
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IBundleInfo.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBundleInfo.cs
new file mode 100644
index 00000000..a4d07597
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IBundleInfo.cs
@@ -0,0 +1,54 @@
+// 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.BootstrapperApplicationApi
+{
+    using System.Collections.Generic;
+
+    /// <summary>
+    /// BA manifest data.
+    /// </summary>
+    public interface IBundleInfo
+    {
+        /// <summary>
+        /// The name of the variable that contains the path to the bundle's log.
+        /// </summary>
+        string LogVariable { get; }
+
+        /// <summary>
+        /// Bundle/@Name
+        /// </summary>
+        string Name { get; }
+
+        /// <summary>
+        /// Variables that were marked with bal:Overridable="yes".
+        /// </summary>
+        IOverridableVariables OverridableVariables { get; }
+
+        /// <summary>
+        /// The packages in the bundle's chain.
+        /// </summary>
+        IDictionary<string, IPackageInfo> Packages { get; }
+
+        /// <summary>
+        /// Whether the bundle is per-machine or per-user.
+        /// </summary>
+        bool PerMachine { get; }
+
+        /// <summary>
+        /// Adds a related bundle as a package.
+        /// </summary>
+        /// <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(string productCode, RelationType relationType, bool perMachine, string version);
+
+        /// <summary>
+        /// Adds an update bundle as a package.
+        /// </summary>
+        /// <param name="packageId">Package id added as update bundle.</param>
+        /// <returns>The created <see cref="IPackageInfo"/>.</returns>
+        IPackageInfo AddUpdateBundleAsPackage(string packageId);
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IDefaultBootstrapperApplication.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IDefaultBootstrapperApplication.cs
new file mode 100644
index 00000000..ad51b2be
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IDefaultBootstrapperApplication.cs
@@ -0,0 +1,436 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+
+    /// <summary>
+    /// Interface for built-in implementation of <see cref="IBootstrapperApplication"/>.
+    /// </summary>
+    public interface IDefaultBootstrapperApplication : IBootstrapperApplication
+    {
+        /// <summary>
+        /// Fired when the engine has begun installing the bundle.
+        /// </summary>
+        event EventHandler<ApplyBeginEventArgs> ApplyBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed installing the bundle.
+        /// </summary>
+        event EventHandler<ApplyCompleteEventArgs> ApplyComplete;
+
+        /// <summary>
+        /// Fired when the plan determined that nothing should happen to prevent downgrading.
+        /// </summary>
+        event EventHandler<ApplyDowngradeEventArgs> ApplyDowngrade;
+
+        /// <summary>
+        /// Fired when the engine is about to begin an MSI transaction.
+        /// </summary>
+        event EventHandler<BeginMsiTransactionBeginEventArgs> BeginMsiTransactionBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed beginning an MSI transaction.
+        /// </summary>
+        event EventHandler<BeginMsiTransactionCompleteEventArgs> BeginMsiTransactionComplete;
+
+        /// <summary>
+        /// Fired when the engine has begun acquiring the payload or container.
+        /// The BA can change the source using <see cref="IEngine.SetLocalSource(String, String, String)"/>
+        /// or <see cref="IEngine.SetDownloadSource(String, String, String, String, String)"/>.
+        /// </summary>
+        event EventHandler<CacheAcquireBeginEventArgs> CacheAcquireBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed the acquisition of the payload or container.
+        /// The BA can change the source using <see cref="IEngine.SetLocalSource(String, String, String)"/>
+        /// or <see cref="IEngine.SetDownloadSource(String, String, String, String, String)"/>.
+        /// </summary>
+        event EventHandler<CacheAcquireCompleteEventArgs> CacheAcquireComplete;
+
+        /// <summary>
+        /// Fired when the engine has progress acquiring the payload or container.
+        /// </summary>
+        event EventHandler<CacheAcquireProgressEventArgs> CacheAcquireProgress;
+
+        /// <summary>
+        /// Fired by the engine to allow the BA to override the acquisition action.
+        /// </summary>
+        event EventHandler<CacheAcquireResolvingEventArgs> CacheAcquireResolving;
+
+        /// <summary>
+        /// Fired when the engine has begun caching the installation sources.
+        /// </summary>
+        event EventHandler<CacheBeginEventArgs> CacheBegin;
+
+        /// <summary>
+        /// Fired after the engine has cached the installation sources.
+        /// </summary>
+        event EventHandler<CacheCompleteEventArgs> CacheComplete;
+
+        /// <summary>
+        /// Fired when the engine begins the verification of the payload or container that was already in the package cache.
+        /// </summary>
+        event EventHandler<CacheContainerOrPayloadVerifyBeginEventArgs> CacheContainerOrPayloadVerifyBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed the verification of the payload or container that was already in the package cache.
+        /// </summary>
+        event EventHandler<CacheContainerOrPayloadVerifyCompleteEventArgs> CacheContainerOrPayloadVerifyComplete;
+
+        /// <summary>
+        /// Fired when the engine has progress verifying the payload or container that was already in the package cache.
+        /// </summary>
+        event EventHandler<CacheContainerOrPayloadVerifyProgressEventArgs> CacheContainerOrPayloadVerifyProgress;
+
+        /// <summary>
+        /// Fired when the engine has begun caching a specific package.
+        /// </summary>
+        event EventHandler<CachePackageBeginEventArgs> CachePackageBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed caching a specific package.
+        /// </summary>
+        event EventHandler<CachePackageCompleteEventArgs> CachePackageComplete;
+
+        /// <summary>
+        /// Fired when the engine failed validating a package in the package cache that is non-vital to execution.
+        /// </summary>
+        event EventHandler<CachePackageNonVitalValidationFailureEventArgs> CachePackageNonVitalValidationFailure;
+
+        /// <summary>
+        /// Fired when the engine begins the extraction of the payload from the container.
+        /// </summary>
+        event EventHandler<CachePayloadExtractBeginEventArgs> CachePayloadExtractBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed the extraction of the payload from the container.
+        /// </summary>
+        event EventHandler<CachePayloadExtractCompleteEventArgs> CachePayloadExtractComplete;
+
+        /// <summary>
+        /// Fired when the engine has progress extracting the payload from the container.
+        /// </summary>
+        event EventHandler<CachePayloadExtractProgressEventArgs> CachePayloadExtractProgress;
+
+        /// <summary>
+        /// Fired when the engine begins the verification of the acquired payload or container.
+        /// </summary>
+        event EventHandler<CacheVerifyBeginEventArgs> CacheVerifyBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed the verification of the acquired payload or container.
+        /// </summary>
+        event EventHandler<CacheVerifyCompleteEventArgs> CacheVerifyComplete;
+
+        /// <summary>
+        /// Fired when the engine has progress verifying the payload or container.
+        /// </summary>
+        event EventHandler<CacheVerifyProgressEventArgs> CacheVerifyProgress;
+
+        /// <summary>
+        /// Fired when the engine is about to commit an MSI transaction.
+        /// </summary>
+        event EventHandler<CommitMsiTransactionBeginEventArgs> CommitMsiTransactionBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed comitting an MSI transaction.
+        /// </summary>
+        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;
+
+        /// <summary>
+        /// Fired when a package was not detected but a package using the same provider key was.
+        /// </summary>
+        event EventHandler<DetectCompatibleMsiPackageEventArgs> DetectCompatibleMsiPackage;
+
+        /// <summary>
+        /// Fired when the detection phase has completed.
+        /// </summary>
+        event EventHandler<DetectCompleteEventArgs> DetectComplete;
+
+        /// <summary>
+        /// Fired when a forward compatible bundle is detected.
+        /// </summary>
+        event EventHandler<DetectForwardCompatibleBundleEventArgs> DetectForwardCompatibleBundle;
+
+        /// <summary>
+        /// Fired when a feature in an MSI package has been detected.
+        /// </summary>
+        event EventHandler<DetectMsiFeatureEventArgs> DetectMsiFeature;
+
+        /// <summary>
+        /// Fired when the detection for a specific package has begun.
+        /// </summary>
+        event EventHandler<DetectPackageBeginEventArgs> DetectPackageBegin;
+
+        /// <summary>
+        /// Fired when the detection for a specific package has completed.
+        /// </summary>
+        event EventHandler<DetectPackageCompleteEventArgs> DetectPackageComplete;
+
+        /// <summary>
+        /// Fired when the engine detects a target product for an MSP package.
+        /// </summary>
+        event EventHandler<DetectPatchTargetEventArgs> DetectPatchTarget;
+
+        /// <summary>
+        /// Fired when a related bundle has been detected for a bundle.
+        /// </summary>
+        event EventHandler<DetectRelatedBundleEventArgs> DetectRelatedBundle;
+
+        /// <summary>
+        /// Fired when a related bundle has been detected for a bundle package.
+        /// </summary>
+        event EventHandler<DetectRelatedBundlePackageEventArgs> DetectRelatedBundlePackage;
+
+        /// <summary>
+        /// Fired when a related MSI package has been detected for a package.
+        /// </summary>
+        event EventHandler<DetectRelatedMsiPackageEventArgs> DetectRelatedMsiPackage;
+
+        /// <summary>
+        /// Fired when the update detection has found a potential update candidate.
+        /// </summary>
+        event EventHandler<DetectUpdateEventArgs> DetectUpdate;
+
+        /// <summary>
+        /// Fired when the update detection phase has begun.
+        /// </summary>
+        event EventHandler<DetectUpdateBeginEventArgs> DetectUpdateBegin;
+
+        /// <summary>
+        /// Fired when the update detection phase has completed.
+        /// </summary>
+        event EventHandler<DetectUpdateCompleteEventArgs> DetectUpdateComplete;
+
+        /// <summary>
+        /// Fired when the engine is about to start the elevated process.
+        /// </summary>
+        event EventHandler<ElevateBeginEventArgs> ElevateBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed starting the elevated process.
+        /// </summary>
+        event EventHandler<ElevateCompleteEventArgs> ElevateComplete;
+
+        /// <summary>
+        /// Fired when the engine has encountered an error.
+        /// </summary>
+        event EventHandler<ErrorEventArgs> Error;
+
+        /// <summary>
+        /// Fired when the engine has begun installing packages.
+        /// </summary>
+        event EventHandler<ExecuteBeginEventArgs> ExecuteBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed installing packages.
+        /// </summary>
+        event EventHandler<ExecuteCompleteEventArgs> ExecuteComplete;
+
+        /// <summary>
+        /// Fired when a package sends a files in use installation message.
+        /// </summary>
+        event EventHandler<ExecuteFilesInUseEventArgs> ExecuteFilesInUse;
+
+        /// <summary>
+        /// Fired when Windows Installer sends an installation message.
+        /// </summary>
+        event EventHandler<ExecuteMsiMessageEventArgs> ExecuteMsiMessage;
+
+        /// <summary>
+        /// Fired when the engine has begun installing a specific package.
+        /// </summary>
+        event EventHandler<ExecutePackageBeginEventArgs> ExecutePackageBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed installing a specific package.
+        /// </summary>
+        event EventHandler<ExecutePackageCompleteEventArgs> ExecutePackageComplete;
+
+        /// <summary>
+        /// Fired when a package that spawned a process is cancelled.
+        /// </summary>
+        event EventHandler<ExecuteProcessCancelEventArgs> ExecuteProcessCancel;
+
+        /// <summary>
+        /// Fired when the engine executes one or more patches targeting a product.
+        /// </summary>
+        event EventHandler<ExecutePatchTargetEventArgs> ExecutePatchTarget;
+
+        /// <summary>
+        /// Fired by the engine while executing a package.
+        /// </summary>
+        event EventHandler<ExecuteProgressEventArgs> ExecuteProgress;
+
+        /// <summary>
+        /// Fired when the engine is about to launch the preapproved executable.
+        /// </summary>
+        event EventHandler<LaunchApprovedExeBeginEventArgs> LaunchApprovedExeBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed launching the preapproved executable.
+        /// </summary>
+        event EventHandler<LaunchApprovedExeCompleteEventArgs> LaunchApprovedExeComplete;
+
+        /// <summary>
+        /// Fired when the engine is about to pause Windows automatic updates.
+        /// </summary>
+        event EventHandler<PauseAutomaticUpdatesBeginEventArgs> PauseAutomaticUpdatesBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed pausing Windows automatic updates.
+        /// </summary>
+        event EventHandler<PauseAutomaticUpdatesCompleteEventArgs> PauseAutomaticUpdatesComplete;
+
+        /// <summary>
+        /// Fired when the engine has begun planning the installation.
+        /// </summary>
+        event EventHandler<PlanBeginEventArgs> PlanBegin;
+
+        /// <summary>
+        /// Fired when the engine plans a new, compatible package using the same provider key.
+        /// </summary>
+        event EventHandler<PlanCompatibleMsiPackageBeginEventArgs> PlanCompatibleMsiPackageBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed planning the installation of a specific package.
+        /// </summary>
+        event EventHandler<PlanCompatibleMsiPackageCompleteEventArgs> PlanCompatibleMsiPackageComplete;
+
+        /// <summary>
+        /// Fired when the engine has completed planning the installation.
+        /// </summary>
+        event EventHandler<PlanCompleteEventArgs> PlanComplete;
+
+        /// <summary>
+        /// Fired when the engine is about to plan a forward compatible bundle.
+        /// </summary>
+        event EventHandler<PlanForwardCompatibleBundleEventArgs> PlanForwardCompatibleBundle;
+
+        /// <summary>
+        /// Fired when the engine has completed planning a compatible package.
+        /// </summary>
+        event EventHandler<PlannedCompatiblePackageEventArgs> PlannedCompatiblePackage;
+
+        /// <summary>
+        /// Fired when the engine has completed planning a package.
+        /// </summary>
+        event EventHandler<PlannedPackageEventArgs> PlannedPackage;
+
+        /// <summary>
+        /// Fired when the engine is about to plan a feature in an MSI package.
+        /// </summary>
+        event EventHandler<PlanMsiFeatureEventArgs> PlanMsiFeature;
+
+        /// <summary>
+        /// Fired when the engine is planning an MSI or MSP package.
+        /// </summary>
+        event EventHandler<PlanMsiPackageEventArgs> PlanMsiPackage;
+
+        /// <summary>
+        /// Fired when the engine has begun getting the BA's input for planning a package.
+        /// </summary>
+        event EventHandler<PlanPackageBeginEventArgs> PlanPackageBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed getting the BA's input for planning a package.
+        /// </summary>
+        event EventHandler<PlanPackageCompleteEventArgs> PlanPackageComplete;
+
+        /// <summary>
+        /// Fired when the engine is about to plan a target of an MSP package.
+        /// </summary>
+        event EventHandler<PlanPatchTargetEventArgs> PlanPatchTarget;
+
+        /// <summary>
+        /// Fired when the engine has begun planning for a related bundle.
+        /// </summary>
+        event EventHandler<PlanRelatedBundleEventArgs> PlanRelatedBundle;
+
+        /// <summary>
+        /// Fired when the engine has begun planning the related bundle relation type.
+        /// </summary>
+        event EventHandler<PlanRelatedBundleTypeEventArgs> PlanRelatedBundleType;
+
+        /// <summary>
+        /// Fired when the engine has begun planning an upgrade related bundle for restoring in case of failure.
+        /// </summary>
+        event EventHandler<PlanRestoreRelatedBundleEventArgs> PlanRestoreRelatedBundle;
+
+        /// <summary>
+        /// Fired when the engine is planning a rollback boundary.
+        /// </summary>
+        event EventHandler<PlanRollbackBoundaryEventArgs> PlanRollbackBoundary;
+
+        /// <summary>
+        /// Fired when the engine has changed progress for the bundle installation.
+        /// </summary>
+        event EventHandler<ProgressEventArgs> Progress;
+
+        /// <summary>
+        /// Fired when the engine has begun registering the location and visibility of the bundle.
+        /// </summary>
+        event EventHandler<RegisterBeginEventArgs> RegisterBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed registering the location and visibility of the bundle.
+        /// </summary>
+        event EventHandler<RegisterCompleteEventArgs> RegisterComplete;
+
+        /// <summary>
+        /// Fired when the engine is about to rollback an MSI transaction.
+        /// </summary>
+        event EventHandler<RollbackMsiTransactionBeginEventArgs> RollbackMsiTransactionBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed rolling back an MSI transaction.
+        /// </summary>
+        event EventHandler<RollbackMsiTransactionCompleteEventArgs> RollbackMsiTransactionComplete;
+
+        /// <summary>
+        /// Fired when the engine is shutting down the bootstrapper application.
+        /// </summary>
+        event EventHandler<ShutdownEventArgs> Shutdown;
+
+        /// <summary>
+        /// Fired when the engine is starting up the bootstrapper application.
+        /// </summary>
+        event EventHandler<StartupEventArgs> Startup;
+
+        /// <summary>
+        /// Fired when the engine is about to take a system restore point.
+        /// </summary>
+        event EventHandler<SystemRestorePointBeginEventArgs> SystemRestorePointBegin;
+
+        /// <summary>
+        /// Fired when the engine has completed taking a system restore point.
+        /// </summary>
+        event EventHandler<SystemRestorePointCompleteEventArgs> SystemRestorePointComplete;
+
+        /// <summary>
+        /// Fired when the engine unregisters the bundle.
+        /// </summary>
+        event EventHandler<UnregisterBeginEventArgs> UnregisterBegin;
+
+        /// <summary>
+        /// Fired when the engine unregistration is complete.
+        /// </summary>
+        event EventHandler<UnregisterCompleteEventArgs> UnregisterComplete;
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IEngine.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IEngine.cs
new file mode 100644
index 00000000..8e6a293b
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IEngine.cs
@@ -0,0 +1,230 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.ComponentModel;
+    using System.Security;
+
+    /// <summary>
+    /// High level abstraction over the <see cref="IBootstrapperEngine"/> interface.
+    /// </summary>
+    public interface IEngine
+    {
+        /// <summary>
+        /// Gets the number of packages in the bundle.
+        /// </summary>
+        int PackageCount { get; }
+
+        /// <summary>
+        /// Install the packages.
+        /// </summary>
+        /// <param name="hwndParent">The parent window for the installation user interface.</param>
+        void Apply(IntPtr hwndParent);
+
+        /// <summary>
+        /// Close the splash screen if it is still open. Does nothing if the splash screen is not or
+        /// never was opened.
+        /// </summary>
+        void CloseSplashScreen();
+
+        /// <returns>0 if equal, 1 if version1 &gt; version2, -1 if version1 &lt; version2</returns>
+        int CompareVersions(string version1, string version2);
+
+        /// <summary>
+        /// Checks if a variable exists in the engine.
+        /// </summary>
+        /// <param name="name">The name of the variable.</param>
+        /// <returns>Whether the variable exists.</returns>
+        bool ContainsVariable(string name);
+
+        /// <summary>
+        /// Determine if all installation conditions are fulfilled.
+        /// </summary>
+        void Detect();
+
+        /// <summary>
+        /// Determine if all installation conditions are fulfilled.
+        /// </summary>
+        /// <param name="hwndParent">The parent window for the installation user interface.</param>
+        void Detect(IntPtr hwndParent);
+
+        /// <summary>
+        /// Elevate the install.
+        /// </summary>
+        /// <param name="hwndParent">The parent window of the elevation dialog.</param>
+        /// <returns>true if elevation succeeded; otherwise, false if the user cancelled.</returns>
+        /// <exception cref="Win32Exception">A Win32 error occurred.</exception>
+        bool Elevate(IntPtr hwndParent);
+
+        /// <summary>
+        /// Escapes the input string.
+        /// </summary>
+        /// <param name="input">The string to escape.</param>
+        /// <returns>The escaped string.</returns>
+        /// <exception cref="Win32Exception">A Win32 error occurred.</exception>
+        string EscapeString(string input);
+
+        /// <summary>
+        /// Evaluates the <paramref name="condition"/> string.
+        /// </summary>
+        /// <param name="condition">The string representing the condition to evaluate.</param>
+        /// <returns>Whether the condition evaluated to true or false.</returns>
+        bool EvaluateCondition(string condition);
+
+        /// <summary>
+        /// Formats the input string.
+        /// </summary>
+        /// <param name="format">The string to format.</param>
+        /// <returns>The formatted string.</returns>
+        /// <exception cref="Win32Exception">A Win32 error occurred.</exception>
+        string FormatString(string format);
+
+        /// <summary>
+        /// Gets numeric variables for the engine.
+        /// </summary>
+        /// <param name="name">The name of the variable.</param>
+        long GetVariableNumeric(string name);
+
+        /// <summary>
+        /// Gets string variables for the engine using SecureStrings.
+        /// </summary>
+        /// <param name="name">The name of the variable.</param>
+        SecureString GetVariableSecureString(string name);
+
+        /// <summary>
+        /// Gets string variables for the engine.
+        /// </summary>
+        /// <param name="name">The name of the variable.</param>
+        string GetVariableString(string name);
+
+        /// <summary>
+        /// Gets <see cref="Version"/> variables for the engine.
+        /// </summary>
+        /// <param name="name">The name of the variable.</param>
+        string GetVariableVersion(string name);
+
+        /// <summary>
+        /// Gets persisted variables from a related bundle.
+        /// </summary>
+        /// <param name="bundleId">The BundleId of the related bundle.</param>
+        /// <param name="name">The name of the variable.</param>
+        string GetRelatedBundleVariable(string bundleId, string name);
+
+        /// <summary>
+        /// Launches a preapproved executable elevated.  As long as the engine already elevated, there will be no UAC prompt.
+        /// </summary>
+        /// <param name="hwndParent">The parent window of the elevation dialog (if the engine hasn't elevated yet).</param>
+        /// <param name="approvedExeForElevationId">Id of the ApprovedExeForElevation element specified when the bundle was authored.</param>
+        /// <param name="arguments">Optional arguments.</param>
+        void LaunchApprovedExe(IntPtr hwndParent, string approvedExeForElevationId, string arguments);
+
+        /// <summary>
+        /// Launches a preapproved executable elevated.  As long as the engine already elevated, there will be no UAC prompt.
+        /// </summary>
+        /// <param name="hwndParent">The parent window of the elevation dialog (if the engine hasn't elevated yet).</param>
+        /// <param name="approvedExeForElevationId">Id of the ApprovedExeForElevation element specified when the bundle was authored.</param>
+        /// <param name="arguments">Optional arguments.</param>
+        /// <param name="waitForInputIdleTimeout">Timeout in milliseconds. When set to something other than zero, the engine will call WaitForInputIdle for the new process with this timeout before calling OnLaunchApprovedExeComplete.</param>
+        void LaunchApprovedExe(IntPtr hwndParent, string approvedExeForElevationId, string arguments, int waitForInputIdleTimeout);
+
+        /// <summary>
+        /// Logs the <paramref name="message"/>.
+        /// </summary>
+        /// <param name="level">The logging level.</param>
+        /// <param name="message">The message to log.</param>
+        void Log(LogLevel level, string message);
+
+        /// <summary>
+        /// Determine the installation sequencing and costing.
+        /// </summary>
+        /// <param name="action">The action to perform when planning.</param>
+        void Plan(LaunchAction action);
+
+        /// <summary>
+        /// Set the update information for a bundle.
+        /// </summary>
+        /// <param name="localSource">Optional local source path for the update. Default is "update\[OriginalNameOfBundle].exe".</param>
+        /// <param name="downloadSource">Optional download source for the update.</param>
+        /// <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>
+        /// <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.
+        /// </summary>
+        /// <param name="url">URL of the update feed.</param>
+        void SetUpdateSource(string url);
+
+        /// <summary>
+        /// Set the local source for a package or container.
+        /// </summary>
+        /// <param name="packageOrContainerId">The id that uniquely identifies the package or container.</param>
+        /// <param name="payloadId">The id that uniquely identifies the payload.</param>
+        /// <param name="path">The new source path.</param>
+        void SetLocalSource(string packageOrContainerId, string payloadId, string path);
+
+        /// <summary>
+        /// Set the new download URL for a package or container.
+        /// </summary>
+        /// <param name="packageOrContainerId">The id that uniquely identifies the package or container.</param>
+        /// <param name="payloadId">The id that uniquely identifies the payload.</param>
+        /// <param name="url">The new url.</param>
+        /// <param name="user">The user name for proxy authentication.</param>
+        /// <param name="password">The password for proxy authentication.</param>
+        void SetDownloadSource(string packageOrContainerId, string payloadId, string url, string user, string password);
+
+        /// <summary>
+        /// Sets numeric variables for the engine.
+        /// </summary>
+        /// <param name="name">The name of the variable.</param>
+        /// <param name="value">The value to set.</param>
+        void SetVariableNumeric(string name, long value);
+
+        /// <summary>
+        /// Sets string variables for the engine using SecureStrings.
+        /// </summary>
+        /// <param name="name">The name of the variable.</param>
+        /// <param name="value">The value to set.</param>
+        /// <param name="formatted">False if the value is a literal string.</param>
+        void SetVariableString(string name, SecureString value, bool formatted);
+
+        /// <summary>
+        /// Sets string variables for the engine.
+        /// </summary>
+        /// <param name="name">The name of the variable.</param>
+        /// <param name="value">The value to set.</param>
+        /// <param name="formatted">False if the value is a literal string.</param>
+        void SetVariableString(string name, string value, bool formatted);
+
+        /// <summary>
+        /// Sets version variables for the engine.
+        /// </summary>
+        /// <param name="name">The name of the variable.</param>
+        /// <param name="value">The value to set.</param>
+        void SetVariableVersion(string name, string value);
+
+        /// <summary>
+        /// Sends error message when embedded.
+        /// </summary>
+        /// <param name="errorCode">Error code.</param>
+        /// <param name="message">Error message.</param>
+        /// <param name="uiHint">UI buttons to show on error dialog.</param>
+        int SendEmbeddedError(int errorCode, string message, int uiHint);
+
+        /// <summary>
+        /// Sends progress percentages when embedded.
+        /// </summary>
+        /// <param name="progressPercentage">Percentage completed thus far.</param>
+        /// <param name="overallPercentage">Overall percentage completed.</param>
+        int SendEmbeddedProgress(int progressPercentage, int overallPercentage);
+
+        /// <summary>
+        /// Shuts down the engine.
+        /// </summary>
+        /// <param name="exitCode">Exit code indicating reason for shut down.</param>
+        void Quit(int exitCode);
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IMbaCommand.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IMbaCommand.cs
new file mode 100644
index 00000000..37640a87
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IMbaCommand.cs
@@ -0,0 +1,35 @@
+// 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.BootstrapperApplicationApi
+{
+    using System.Collections.Generic;
+
+    /// <summary>
+    /// Command information parsed from the command line.
+    /// </summary>
+    public interface IMbaCommand
+    {
+        /// <summary>
+        /// Gets the action to perform if a reboot is required.
+        /// </summary>
+        Restart Restart { get; }
+
+        /// <summary>
+        /// The command line arguments not parsed into <see cref="IBootstrapperCommand"/> or <see cref="IMbaCommand"/>.
+        /// </summary>
+        string[] UnknownCommandLineArgs { get; }
+
+        /// <summary>
+        /// The variables that were parsed from the command line.
+        /// Key = variable name, Value = variable value.
+        /// </summary>
+        KeyValuePair<string, string>[] Variables { get; }
+
+        /// <summary>
+        /// Sets overridable variables from the command line.
+        /// </summary>
+        /// <param name="overridableVariables">The overridable variable information from <see cref="IBootstrapperApplicationData"/>.</param>
+        /// <param name="engine">The engine.</param>
+        void SetOverridableVariables(IOverridableVariables overridableVariables, IEngine engine);
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IOverridableVariableInfo.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IOverridableVariableInfo.cs
new file mode 100644
index 00000000..173963a8
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IOverridableVariableInfo.cs
@@ -0,0 +1,15 @@
+// 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.BootstrapperApplicationApi
+{
+    /// <summary>
+    /// Overridable variable from the BA manifest.
+    /// </summary>
+    public interface IOverridableVariableInfo
+    {
+        /// <summary>
+        /// The Variable name.
+        /// </summary>
+        string Name { get; }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IOverridableVariables.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IOverridableVariables.cs
new file mode 100644
index 00000000..2cf7b8d9
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IOverridableVariables.cs
@@ -0,0 +1,37 @@
+// 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.BootstrapperApplicationApi
+{
+    using System.Collections.Generic;
+
+    /// <summary>
+    /// The case sensitivity of variables from the command line.
+    /// </summary>
+    public enum VariableCommandLineType
+    {
+        /// <summary>
+        /// All variable names specified on the command line must match the case specified when building the bundle.
+        /// </summary>
+        CaseSensitive,
+        /// <summary>
+        /// Variable names specified on the command line do not have to match the case specified when building the bundle.
+        /// </summary>
+        CaseInsensitive,
+    }
+
+    /// <summary>
+    /// Overridable variable information from the BA manifest.
+    /// </summary>
+    public interface IOverridableVariables
+    {
+        /// <summary>
+        /// The <see cref="VariableCommandLineType"/> of the bundle.
+        /// </summary>
+        VariableCommandLineType CommandLineType { get; }
+
+        /// <summary>
+        /// Variable Dictionary of variable name to <see cref="IOverridableVariableInfo"/>.
+        /// </summary>
+        IDictionary<string, IOverridableVariableInfo> Variables { get; }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/IPackageInfo.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/IPackageInfo.cs
new file mode 100644
index 00000000..e2512584
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/IPackageInfo.cs
@@ -0,0 +1,100 @@
+// 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.BootstrapperApplicationApi
+{
+    /// <summary>
+    /// Package information from the BA manifest.
+    /// </summary>
+    public interface IPackageInfo
+    {
+        /// <summary>
+        /// The authored cache strategy for this package.
+        /// </summary>
+        BOOTSTRAPPER_CACHE_TYPE CacheType { get; }
+
+        /// <summary>
+        /// Place for the BA to store it's own custom data for this package.
+        /// </summary>
+        object CustomData { get; set; }
+
+        /// <summary>
+        /// The package's description.
+        /// </summary>
+        string Description { get; }
+
+        /// <summary>
+        /// The authored bal:DisplayInternalUICondition.
+        /// </summary>
+        string DisplayInternalUICondition { get; }
+
+        /// <summary>
+        /// The package's display name.
+        /// </summary>
+        string DisplayName { get; }
+
+        /// <summary>
+        /// The package's Id.
+        /// </summary>
+        string Id { get; }
+
+        /// <summary>
+        /// The authored InstallCondition.
+        /// </summary>
+        string InstallCondition { get; }
+
+        /// <summary>
+        /// The authored RepairCondition.
+        /// </summary>
+        string RepairCondition { get; }
+
+        /// <summary>
+        /// Whether the bundle should ever recommend the package to be uninstalled.
+        /// </summary>
+        bool Permanent { get; }
+
+        /// <summary>
+        /// Whether the package should be installed by the prereq BA for managed bootstrapper applications.
+        /// </summary>
+        bool PrereqPackage { get; }
+
+        /// <summary>
+        /// The file name of the license file to be shown by the prereq BA.
+        /// </summary>
+        string PrereqLicenseFile { get; }
+
+        /// <summary>
+        /// The URL of the license to be shown by the prereq BA.
+        /// </summary>
+        string PrereqLicenseUrl { get; }
+
+        /// <summary>
+        /// See <see cref="WixToolset.BootstrapperApplicationApi.PrimaryPackageType"/>
+        /// </summary>
+        PrimaryPackageType PrimaryPackageType { get; }
+
+        /// <summary>
+        /// The package's ProductCode.
+        /// </summary>
+        string ProductCode { get; }
+
+        /// <summary>
+        /// The type of the package.
+        /// </summary>
+        PackageType Type { get; }
+
+        /// <summary>
+        /// The package's UpgradeCode.
+        /// </summary>
+        string UpgradeCode { get; }
+
+        /// <summary>
+        /// The package's version.
+        /// </summary>
+        string Version { get; }
+
+        /// <summary>
+        /// Whether the package's failure can be ignored while executing the chain.
+        /// </summary>
+        bool Vital { get; }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/ManagedBootstrapperApplication.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/ManagedBootstrapperApplication.cs
new file mode 100644
index 00000000..77c5eaca
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/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.BootstrapperApplicationApi
+{
+    /// <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.BootstrapperApplicationApi/MbaCommand.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/MbaCommand.cs
new file mode 100644
index 00000000..c46b5844
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/MbaCommand.cs
@@ -0,0 +1,38 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Collections.Generic;
+
+    /// <summary>
+    /// Default implementation of <see cref="IMbaCommand"/>.
+    /// </summary>
+    internal sealed class MbaCommand : IMbaCommand
+    {
+        public Restart Restart { get; internal set; }
+
+        public string[] UnknownCommandLineArgs { get; internal set; }
+
+        public KeyValuePair<string, string>[] Variables { get; internal set; }
+
+        internal MbaCommand() { }
+
+        public void SetOverridableVariables(IOverridableVariables overridableVariables, IEngine engine)
+        {
+            foreach (var kvp in this.Variables)
+            {
+                var key = kvp.Key;
+
+                if (!overridableVariables.Variables.TryGetValue(key, out var overridableVariable))
+                {
+                    engine.Log(LogLevel.Error, String.Format("Ignoring attempt to set non-overridable variable: '{0}'.", key));
+                }
+                else
+                {
+                    engine.SetVariableString(overridableVariable.Name, kvp.Value, false);
+                }
+            }
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/MbaNative.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/MbaNative.cs
new file mode 100644
index 00000000..6e135fc3
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/MbaNative.cs
@@ -0,0 +1,18 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+
+    internal static class MbaNative
+    {
+        [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
+        internal static extern void BalDebuggerCheck();
+
+        [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
+        internal static extern void BootstrapperApplicationRun(
+            [MarshalAs(UnmanagedType.Interface)] IBootstrapperApplication pBA
+            );
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/NativeMethods.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/NativeMethods.cs
new file mode 100644
index 00000000..4ef9f35e
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/NativeMethods.cs
@@ -0,0 +1,49 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// Contains native constants, functions, and structures for this assembly.
+    /// </summary>
+    internal static class NativeMethods
+    {
+        #region Error Constants
+        internal const int S_OK = 0;
+        internal const int E_MOREDATA = unchecked((int)0x800700ea);
+        internal const int E_INSUFFICIENT_BUFFER = unchecked((int)0x8007007a);
+        internal const int E_CANCELLED = unchecked((int)0x800704c7);
+        internal const int E_ALREADYINITIALIZED = unchecked((int)0x800704df);
+        internal const int E_NOTFOUND = unchecked((int)0x80070490);
+        internal const int E_NOTIMPL = unchecked((int)0x80004001);
+        internal const int E_UNEXPECTED = unchecked((int)0x8000ffff);
+        #endregion
+
+        #region Functions
+        [DllImport("shell32.dll", ExactSpelling = true, SetLastError = true)]
+        internal static extern IntPtr CommandLineToArgvW(
+            [MarshalAs(UnmanagedType.LPWStr)] string lpCmdLine,
+            out int pNumArgs
+            );
+
+        [DllImport("kernel32.dll", ExactSpelling = true, SetLastError = true)]
+        internal static extern IntPtr LocalFree(
+            IntPtr hMem
+            );
+        #endregion
+    }
+
+    #region SafeHandles
+    internal abstract class SafeHandleZeroIsDefaultAndInvalid : SafeHandle
+    {
+        public SafeHandleZeroIsDefaultAndInvalid() : base(IntPtr.Zero, true) { }
+
+        public override bool IsInvalid
+        {
+            get { return this.handle == IntPtr.Zero; }
+        }
+    }
+    #endregion
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/OverridableVariableInfo.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/OverridableVariableInfo.cs
new file mode 100644
index 00000000..8b90c588
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/OverridableVariableInfo.cs
@@ -0,0 +1,15 @@
+// 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.BootstrapperApplicationApi
+{
+    /// <summary>
+    /// Default implementation of <see cref="IOverridableVariableInfo"/>.
+    /// </summary>
+    internal class OverridableVariableInfo : IOverridableVariableInfo
+    {
+        /// <inheritdoc />
+        public string Name { get; internal set; }
+
+        internal OverridableVariableInfo() { }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/OverridableVariables.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/OverridableVariables.cs
new file mode 100644
index 00000000..98f8ec81
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/OverridableVariables.cs
@@ -0,0 +1,87 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Xml;
+    using System.Xml.XPath;
+
+    /// <summary>
+    /// Default implementation of <see cref="IOverridableVariables"/>.
+    /// </summary>
+    public class OverridableVariablesInfo : IOverridableVariables
+    {
+        /// <inheritdoc />
+        public VariableCommandLineType CommandLineType { get; internal set; }
+
+        /// <inheritdoc />
+        public IDictionary<string, IOverridableVariableInfo> Variables { get; internal set; }
+
+        internal OverridableVariablesInfo() { }
+
+        /// <summary>
+        /// Parses the overridable variable info from the BA manifest.
+        /// </summary>
+        /// <param name="root">XML root</param>
+        /// <returns>The parsed information.</returns>
+        public static IOverridableVariables ParseFromXml(XPathNavigator root)
+        {
+            XmlNamespaceManager namespaceManager = new XmlNamespaceManager(root.NameTable);
+            namespaceManager.AddNamespace("p", BootstrapperApplicationData.XMLNamespace);
+            XPathNavigator commandLineNode = root.SelectSingleNode("/p:BootstrapperApplicationData/p:WixStdbaCommandLine", namespaceManager);
+            XPathNodeIterator nodes = root.Select("/p:BootstrapperApplicationData/p:WixStdbaOverridableVariable", namespaceManager);
+
+            var overridableVariables = new OverridableVariablesInfo();
+            IEqualityComparer<string> variableNameComparer;
+
+            if (commandLineNode == null)
+            {
+                overridableVariables.CommandLineType = VariableCommandLineType.CaseSensitive;
+                variableNameComparer = StringComparer.InvariantCulture;
+            }
+            else
+            {
+                string variablesValue = BootstrapperApplicationData.GetAttribute(commandLineNode, "Variables");
+
+                if (variablesValue == null)
+                {
+                    throw new Exception("Failed to get command line variable type.");
+                }
+
+                if (variablesValue.Equals("caseInsensitive", StringComparison.InvariantCulture))
+                {
+                    overridableVariables.CommandLineType = VariableCommandLineType.CaseInsensitive;
+                    variableNameComparer = StringComparer.InvariantCultureIgnoreCase;
+                }
+                else if (variablesValue.Equals("caseSensitive", StringComparison.InvariantCulture))
+                {
+                    overridableVariables.CommandLineType = VariableCommandLineType.CaseSensitive;
+                    variableNameComparer = StringComparer.InvariantCulture;
+                }
+                else
+                {
+                    throw new Exception(String.Format("Unknown command line variable type: '{0}'", variablesValue));
+                }
+            }
+
+            overridableVariables.Variables = new Dictionary<string, IOverridableVariableInfo>(variableNameComparer);
+
+            foreach (XPathNavigator node in nodes)
+            {
+                var variable = new OverridableVariableInfo();
+
+                string name = BootstrapperApplicationData.GetAttribute(node, "Name");
+                if (name == null)
+                {
+                    throw new Exception("Failed to get name for overridable variable.");
+                }
+                variable.Name = name;
+
+                overridableVariables.Variables.Add(variable.Name, variable);
+            }
+
+            return overridableVariables;
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/PackageInfo.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/PackageInfo.cs
new file mode 100644
index 00000000..e835f9ea
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/PackageInfo.cs
@@ -0,0 +1,391 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Xml;
+    using System.Xml.XPath;
+
+    /// <summary>
+    /// The type of package.
+    /// </summary>
+    public enum PackageType
+    {
+        /// <summary>
+        /// Invalid type.
+        /// </summary>
+        Unknown,
+
+        /// <summary>
+        /// ExePackage
+        /// </summary>
+        Exe,
+
+        /// <summary>
+        /// MsiPackage
+        /// </summary>
+        Msi,
+
+        /// <summary>
+        /// MspPackage
+        /// </summary>
+        Msp,
+
+        /// <summary>
+        /// MsuPackage
+        /// </summary>
+        Msu,
+
+        /// <summary>
+        /// Related bundle of type Upgrade
+        /// </summary>
+        UpgradeBundle,
+
+        /// <summary>
+        /// Related bundle of type Addon
+        /// </summary>
+        AddonBundle,
+
+        /// <summary>
+        /// Related bundle of type Patch
+        /// </summary>
+        PatchBundle,
+
+        /// <summary>
+        /// Related bundle of type Update
+        /// </summary>
+        UpdateBundle,
+
+        /// <summary>
+        /// BundlePackage
+        /// </summary>
+        ChainBundle,
+    }
+
+    /// <summary>
+    /// Metadata for BAs like WixInternalUIBootstrapperApplication that only support one main package.
+    /// </summary>
+    public enum PrimaryPackageType
+    {
+        /// <summary>
+        /// Not a primary package.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// The default package if no architecture specific package is available for the current architecture.
+        /// </summary>
+        Default,
+
+        /// <summary>
+        /// The package to use on x86 machines.
+        /// </summary>
+        X86,
+
+        /// <summary>
+        /// The package to use on x64 machines.
+        /// </summary>
+        X64,
+
+        /// <summary>
+        /// The package to use on ARM64 machines.
+        /// </summary>
+        ARM64,
+    }
+
+    /// <summary>
+    /// Default implementation of <see cref="IPackageInfo"/>.
+    /// </summary>
+    public class PackageInfo : IPackageInfo
+    {
+        /// <inheritdoc/>
+        public string Id { get; internal set; }
+
+        /// <inheritdoc/>
+        public string DisplayName { get; internal set; }
+
+        /// <inheritdoc/>
+        public string Description { get; internal set; }
+
+        /// <inheritdoc/>
+        public PackageType Type { get; internal set; }
+
+        /// <inheritdoc/>
+        public bool Permanent { get; internal set; }
+
+        /// <inheritdoc/>
+        public bool Vital { get; internal set; }
+
+        /// <inheritdoc/>
+        public string DisplayInternalUICondition { get; internal set; }
+
+        /// <inheritdoc/>
+        public string ProductCode { get; internal set; }
+
+        /// <inheritdoc/>
+        public string UpgradeCode { get; internal set; }
+
+        /// <inheritdoc/>
+        public string Version { get; internal set; }
+
+        /// <inheritdoc/>
+        public string InstallCondition { get; internal set; }
+
+        /// <inheritdoc/>
+        public string RepairCondition { get; internal set; }
+
+        /// <inheritdoc/>
+        public BOOTSTRAPPER_CACHE_TYPE CacheType { get; internal set; }
+
+        /// <inheritdoc/>
+        public bool PrereqPackage { get; internal set; }
+
+        /// <inheritdoc/>
+        public string PrereqLicenseFile { get; internal set; }
+
+        /// <inheritdoc/>
+        public string PrereqLicenseUrl { get; internal set; }
+
+        /// <inheritdoc/>
+        public PrimaryPackageType PrimaryPackageType { get; internal set; }
+
+        /// <inheritdoc/>
+        public object CustomData { get; set; }
+
+        internal PackageInfo() { }
+
+        /// <summary>
+        /// Parse packages from BootstrapperApplicationData.xml.
+        /// </summary>
+        /// <param name="root">The root node.</param>
+        /// <returns>A dictionary of the packages by Id.</returns>
+        public static IDictionary<string, IPackageInfo> ParsePackagesFromXml(XPathNavigator root)
+        {
+            var packagesById = new Dictionary<string, IPackageInfo>();
+            XmlNamespaceManager namespaceManager = new XmlNamespaceManager(root.NameTable);
+            namespaceManager.AddNamespace("p", BootstrapperApplicationData.XMLNamespace);
+            XPathNodeIterator nodes = root.Select("/p:BootstrapperApplicationData/p:WixPackageProperties", namespaceManager);
+
+            foreach (XPathNavigator node in nodes)
+            {
+                var package = new PackageInfo();
+
+                string id = BootstrapperApplicationData.GetAttribute(node, "Package");
+                if (id == null)
+                {
+                    throw new Exception("Failed to get package identifier for package.");
+                }
+                package.Id = id;
+
+                package.DisplayName = BootstrapperApplicationData.GetAttribute(node, "DisplayName");
+
+                package.Description = BootstrapperApplicationData.GetAttribute(node, "Description");
+
+                PackageType? packageType = GetPackageTypeAttribute(node, "PackageType");
+                if (!packageType.HasValue)
+                {
+                    throw new Exception("Failed to get package type for package.");
+                }
+                package.Type = packageType.Value;
+
+                bool? permanent = BootstrapperApplicationData.GetYesNoAttribute(node, "Permanent");
+                if (!permanent.HasValue)
+                {
+                    throw new Exception("Failed to get permanent settings for package.");
+                }
+                package.Permanent = permanent.Value;
+
+                bool? vital = BootstrapperApplicationData.GetYesNoAttribute(node, "Vital");
+                if (!vital.HasValue)
+                {
+                    throw new Exception("Failed to get vital setting for package.");
+                }
+                package.Vital = vital.Value;
+
+                package.ProductCode = BootstrapperApplicationData.GetAttribute(node, "ProductCode");
+
+                package.UpgradeCode = BootstrapperApplicationData.GetAttribute(node, "UpgradeCode");
+
+                package.Version = BootstrapperApplicationData.GetAttribute(node, "Version");
+
+                package.InstallCondition = BootstrapperApplicationData.GetAttribute(node, "InstallCondition");
+
+                package.RepairCondition = BootstrapperApplicationData.GetAttribute(node, "RepairCondition");
+
+                BOOTSTRAPPER_CACHE_TYPE? cacheType = GetCacheTypeAttribute(node, "Cache");
+                if (!cacheType.HasValue)
+                {
+                    throw new Exception("Failed to get cache type for package.");
+                }
+                package.CacheType = cacheType.Value;
+
+                packagesById.Add(package.Id, package);
+            }
+
+            ParseBalPackageInfoFromXml(root, namespaceManager, packagesById);
+            return packagesById;
+        }
+
+        /// <summary>
+        /// Parse the cache type attribute.
+        /// </summary>
+        /// <param name="node">Package node</param>
+        /// <param name="attributeName">Attribute name</param>
+        /// <returns>The cache type</returns>
+        public static BOOTSTRAPPER_CACHE_TYPE? GetCacheTypeAttribute(XPathNavigator node, string attributeName)
+        {
+            string attributeValue = BootstrapperApplicationData.GetAttribute(node, attributeName);
+
+            if (attributeValue == null)
+            {
+                return null;
+            }
+
+            if (attributeValue.Equals("keep", StringComparison.InvariantCulture))
+            {
+                return BOOTSTRAPPER_CACHE_TYPE.Keep;
+            }
+            else if (attributeValue.Equals("force", StringComparison.InvariantCulture))
+            {
+                return BOOTSTRAPPER_CACHE_TYPE.Force;
+            }
+            else
+            {
+                return BOOTSTRAPPER_CACHE_TYPE.Remove;
+            }
+        }
+
+        /// <summary>
+        /// Parse the package type attribute
+        /// </summary>
+        /// <param name="node">Package node</param>
+        /// <param name="attributeName">Attribute name</param>
+        /// <returns>The package type</returns>
+        public static PackageType? GetPackageTypeAttribute(XPathNavigator node, string attributeName)
+        {
+            string attributeValue = BootstrapperApplicationData.GetAttribute(node, attributeName);
+
+            if (attributeValue == null)
+            {
+                return null;
+            }
+
+            if (attributeValue.Equals("Bundle", StringComparison.InvariantCulture))
+            {
+                return PackageType.ChainBundle;
+            }
+            else if (attributeValue.Equals("Exe", StringComparison.InvariantCulture))
+            {
+                return PackageType.Exe;
+            }
+            else if (attributeValue.Equals("Msi", StringComparison.InvariantCulture))
+            {
+                return PackageType.Msi;
+            }
+            else if (attributeValue.Equals("Msp", StringComparison.InvariantCulture))
+            {
+                return PackageType.Msp;
+            }
+            else if (attributeValue.Equals("Msu", StringComparison.InvariantCulture))
+            {
+                return PackageType.Msu;
+            }
+            else
+            {
+                return PackageType.Unknown;
+            }
+        }
+
+        /// <summary>
+        /// Create <see cref="IPackageInfo"/> from a related bundle.
+        /// </summary>
+        /// <param name="id">Package id</param>
+        /// <param name="relationType">Relation type</param>
+        /// <param name="perMachine">Whether the related bundle is per-machine</param>
+        /// <param name="version">The related bundle's version</param>
+        /// <returns>The package info</returns>
+        public static IPackageInfo GetRelatedBundleAsPackage(string id, RelationType relationType, bool perMachine, string version)
+        {
+            PackageInfo package = new PackageInfo();
+            package.Id = id;
+            package.Version = version;
+
+            switch (relationType)
+            {
+                case RelationType.Addon:
+                    package.Type = PackageType.AddonBundle;
+                    break;
+                case RelationType.Patch:
+                    package.Type = PackageType.PatchBundle;
+                    break;
+                case RelationType.Upgrade:
+                    package.Type = PackageType.UpgradeBundle;
+                    break;
+                default:
+                    throw new Exception(String.Format("Unknown related bundle type: {0}", relationType));
+            }
+
+            return package;
+        }
+
+        /// <summary>
+        /// Create <see cref="IPackageInfo"/> from an update bundle.
+        /// </summary>
+        /// <param name="id">Package id</param>
+        /// <returns>The package info</returns>
+        public static IPackageInfo GetUpdateBundleAsPackage(string id)
+        {
+            PackageInfo package = new PackageInfo();
+            package.Id = id;
+            package.Type = PackageType.UpdateBundle;
+
+            return package;
+        }
+
+        internal static void ParseBalPackageInfoFromXml(XPathNavigator root, XmlNamespaceManager namespaceManager, Dictionary<string, IPackageInfo> packagesById)
+        {
+            XPathNodeIterator nodes = root.Select("/p:BootstrapperApplicationData/p:WixBalPackageInfo", namespaceManager);
+
+            foreach (XPathNavigator node in nodes)
+            {
+                string id = BootstrapperApplicationData.GetAttribute(node, "PackageId");
+                if (id == null)
+                {
+                    throw new Exception("Failed to get package identifier for WixBalPackageInfo.");
+                }
+
+                if (!packagesById.TryGetValue(id, out var ipackage))
+                {
+                    throw new Exception(String.Format("Failed to find package specified in WixBalPackageInfo: {0}", id));
+                }
+
+                var package = (PackageInfo)ipackage;
+
+                package.DisplayInternalUICondition = BootstrapperApplicationData.GetAttribute(node, "DisplayInternalUICondition");
+            }
+
+            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 WixPrereqInformation.");
+                }
+
+                if (!packagesById.TryGetValue(id, out var ipackage))
+                {
+                    throw new Exception(String.Format("Failed to find package specified in WixPrereqInformation: {0}", id));
+                }
+
+                var package = (PackageInfo)ipackage;
+
+                package.PrereqPackage = true;
+                package.PrereqLicenseFile = BootstrapperApplicationData.GetAttribute(node, "LicenseFile");
+                package.PrereqLicenseUrl = BootstrapperApplicationData.GetAttribute(node, "LicenseUrl");
+            }
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/StrUtil.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/StrUtil.cs
new file mode 100644
index 00000000..aeeaac47
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/StrUtil.cs
@@ -0,0 +1,54 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+    using System.Security;
+    using System.Text;
+
+    internal static class StrUtil
+    {
+        [DllImport("mbanative.dll", ExactSpelling = true)]
+        internal static extern void StrFree(
+            IntPtr scz
+            );
+
+        internal sealed class StrHandle : SafeHandleZeroIsDefaultAndInvalid
+        {
+            protected override bool ReleaseHandle()
+            {
+                StrFree(this.handle);
+                return true;
+            }
+
+            public string ToUniString()
+            {
+                return Marshal.PtrToStringUni(this.handle);
+            }
+
+            public SecureString ToSecureString()
+            {
+                if (this.handle == IntPtr.Zero)
+                {
+                    return null;
+                }
+
+                SecureString value = new SecureString();
+                char c;
+                for (int charIndex = 0; ; charIndex++)
+                {
+                    c = (char)Marshal.ReadInt16(this.handle, charIndex * UnicodeEncoding.CharSize);
+                    if (c == '\0')
+                    {
+                        break;
+                    }
+
+                    value.AppendChar(c);
+                }
+
+                return value;
+            }
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/VerUtil.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/VerUtil.cs
new file mode 100644
index 00000000..082ee06c
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/VerUtil.cs
@@ -0,0 +1,146 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+    using System.Text;
+
+    /// <summary>
+    /// Managed wrapper for verutil.
+    /// </summary>
+    public static class VerUtil
+    {
+        [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
+        internal static extern int VerCompareParsedVersions(
+            VersionHandle pVersion1,
+            VersionHandle pVersion2
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
+        internal static extern int VerCompareStringVersions(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion1,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion2,
+            [MarshalAs(UnmanagedType.Bool)] bool fStrict
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
+        internal static extern VersionHandle VerCopyVersion(
+            VersionHandle pSource
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true)]
+        internal static extern void VerFreeVersion(
+            IntPtr pVersion
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
+        internal static extern VersionHandle VerParseVersion(
+            [MarshalAs(UnmanagedType.LPWStr)] string wzVersion,
+            [MarshalAs(UnmanagedType.U4)] uint cchValue,
+            [MarshalAs(UnmanagedType.Bool)] bool fStrict
+            );
+
+        [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
+        internal static extern VersionHandle VerVersionFromQword(
+            [MarshalAs(UnmanagedType.I8)] long qwVersion
+            );
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal struct VersionReleaseLabelStruct
+        {
+            public bool fNumeric;
+            public uint dwValue;
+            public IntPtr cchLabelOffset;
+            public int cchLabel;
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        internal struct VersionStruct
+        {
+            public IntPtr sczVersion;
+            public char chPrefix;
+            public uint dwMajor;
+            public uint dwMinor;
+            public uint dwPatch;
+            public uint dwRevision;
+            public int cReleaseLabels;
+            public IntPtr rgReleaseLabels;
+            public IntPtr cchMetadataOffset;
+            public bool fInvalid;
+            public bool fHasMajor;
+            public bool fHasMinor;
+            public bool fHasPatch;
+            public bool fHasRevision;
+        }
+
+        internal static string VersionStringFromOffset(IntPtr wzVersion, IntPtr cchOffset, int? cchLength = null)
+        {
+            var offset = cchOffset.ToInt64() * UnicodeEncoding.CharSize;
+            var wz = new IntPtr(wzVersion.ToInt64() + offset);
+            if (cchLength.HasValue)
+            {
+                return Marshal.PtrToStringUni(wz, (int)cchLength);
+            }
+            else
+            {
+                return Marshal.PtrToStringUni(wz);
+            }
+        }
+
+        internal sealed class VersionHandle : SafeHandleZeroIsDefaultAndInvalid
+        {
+            protected override bool ReleaseHandle()
+            {
+                VerFreeVersion(this.handle);
+                return true;
+            }
+        }
+
+        /// <returns>0 if equal, 1 if version1 &gt; version2, -1 if version1 &lt; version2</returns>
+        public static int CompareParsedVersions(VerUtilVersion version1, VerUtilVersion version2)
+        {
+            return VerCompareParsedVersions(version1.GetHandle(), version2.GetHandle());
+        }
+
+        /// <returns>0 if equal, 1 if version1 &gt; version2, -1 if version1 &lt; version2</returns>
+        public static int CompareStringVersions(string version1, string version2, bool strict)
+        {
+            return VerCompareStringVersions(version1, version2, strict);
+        }
+
+        /// <summary>
+        /// Clone the version.
+        /// </summary>
+        /// <param name="version">Source version</param>
+        /// <returns>Cloned version</returns>
+        public static VerUtilVersion CopyVersion(VerUtilVersion version)
+        {
+            var handle = VerCopyVersion(version.GetHandle());
+            return new VerUtilVersion(handle);
+        }
+
+        /// <summary>
+        /// Parse a version.
+        /// </summary>
+        /// <param name="version">Source version</param>
+        /// <param name="strict">Whether to throw exception on invalid version.</param>
+        /// <returns>Parsed version</returns>
+        public static VerUtilVersion ParseVersion(string version, bool strict)
+        {
+            var handle = VerParseVersion(version, 0, strict);
+            return new VerUtilVersion(handle);
+        }
+
+        /// <summary>
+        /// Parse version from qword.
+        /// </summary>
+        /// <param name="version">Source version</param>
+        /// <returns>Parsed version</returns>
+        public static VerUtilVersion VersionFromQword(long version)
+        {
+            var handle = VerVersionFromQword(version);
+            return new VerUtilVersion(handle);
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/VerUtilVersion.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/VerUtilVersion.cs
new file mode 100644
index 00000000..65b195a4
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/VerUtilVersion.cs
@@ -0,0 +1,129 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// An enhanced implementation of SemVer 2.0.
+    /// </summary>
+    public sealed class VerUtilVersion : IDisposable
+    {
+        internal VerUtilVersion(VerUtil.VersionHandle handle)
+        {
+            this.Handle = handle;
+
+            var pVersion = handle.DangerousGetHandle();
+            var version = (VerUtil.VersionStruct)Marshal.PtrToStructure(pVersion, typeof(VerUtil.VersionStruct));
+            this.Version = Marshal.PtrToStringUni(version.sczVersion);
+            this.Prefix = version.chPrefix;
+            this.Major = version.dwMajor;
+            this.Minor = version.dwMinor;
+            this.Patch = version.dwPatch;
+            this.Revision = version.dwRevision;
+            this.ReleaseLabels = new VerUtilVersionReleaseLabel[version.cReleaseLabels];
+            this.Metadata = VerUtil.VersionStringFromOffset(version.sczVersion, version.cchMetadataOffset);
+            this.IsInvalid = version.fInvalid;
+            this.HasMajor = version.fHasMajor;
+            this.HasMinor = version.fHasMinor;
+            this.HasPatch = version.fHasPatch;
+            this.HasRevision = version.fHasRevision;
+
+            for (var i = 0; i < version.cReleaseLabels; ++i)
+            {
+                var offset = i * Marshal.SizeOf(typeof(VerUtil.VersionReleaseLabelStruct));
+                var pReleaseLabel = new IntPtr(version.rgReleaseLabels.ToInt64() + offset);
+                this.ReleaseLabels[i] = new VerUtilVersionReleaseLabel(pReleaseLabel, version.sczVersion);
+            }
+        }
+
+        /// <summary>
+        /// String version, which would have stripped the leading 'v'.
+        /// </summary>
+        public string Version { get; private set; }
+
+        /// <summary>
+        /// Prefix character that was stripped from <c>Version</c>, or the null character if there was no prefix.
+        /// </summary>
+        public char Prefix { get; private set; }
+
+        /// <summary>
+        /// For version A.B.C.D, Major is A. It is 0 if not specified.
+        /// </summary>
+        public uint Major { get; private set; }
+
+        /// <summary>
+        /// For version A.B.C.D, Minor is B. It is 0 if not specified.
+        /// </summary>
+        public uint Minor { get; private set; }
+
+        /// <summary>
+        /// For version A.B.C.D, Patch is C. It is 0 if not specified.
+        /// </summary>
+        public uint Patch { get; private set; }
+
+        /// <summary>
+        /// For version A.B.C.D, Revision is D. It is 0 if not specified.
+        /// </summary>
+        public uint Revision { get; private set; }
+
+        /// <summary>
+        /// For version X.Y.Z-releaselabels+metadata, ReleaseLabels is the parsed information for releaselabels.
+        /// </summary>
+        public VerUtilVersionReleaseLabel[] ReleaseLabels { get; private set; }
+
+        /// <summary>
+        /// For version X.Y.Z-releaselabels+metadata, Metadata is the rest of the string after +.
+        /// For invalid versions, it is all of the string after the point where it was an invalid string.
+        /// </summary>
+        public string Metadata { get; private set; }
+
+        /// <summary>
+        /// Whether the version conformed to the spec.
+        /// </summary>
+        public bool IsInvalid { get; private set; }
+
+        /// <summary>
+        /// Whether the Major part was specified.
+        /// </summary>
+        public bool HasMajor { get; private set; }
+
+        /// <summary>
+        /// Whether the Minor part was specified.
+        /// </summary>
+        public bool HasMinor { get; private set; }
+
+        /// <summary>
+        /// Whether the Patch part was specified.
+        /// </summary>
+        public bool HasPatch { get; private set; }
+
+        /// <summary>
+        /// Whether the Revision part was specified.
+        /// </summary>
+        public bool HasRevision { get; private set; }
+
+        /// <inheritdoc/>
+        public void Dispose()
+        {
+            if (this.Handle != null)
+            {
+                this.Handle.Dispose();
+                this.Handle = null;
+            }
+        }
+
+        private VerUtil.VersionHandle Handle { get; set; }
+
+        internal VerUtil.VersionHandle GetHandle()
+        {
+            if (this.Handle == null)
+            {
+                throw new ObjectDisposedException(this.Version);
+            }
+
+            return this.Handle;
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/VerUtilVersionReleaseLabel.cs b/src/api/burn/WixToolset.BootstrapperApplicationApi/VerUtilVersionReleaseLabel.cs
new file mode 100644
index 00000000..03603714
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/VerUtilVersionReleaseLabel.cs
@@ -0,0 +1,36 @@
+// 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.BootstrapperApplicationApi
+{
+    using System;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// A release label from a <see cref="VerUtilVersion"/>.
+    /// </summary>
+    public sealed class VerUtilVersionReleaseLabel
+    {
+        internal VerUtilVersionReleaseLabel(IntPtr pReleaseLabel, IntPtr wzVersion)
+        {
+            var releaseLabel = (VerUtil.VersionReleaseLabelStruct)Marshal.PtrToStructure(pReleaseLabel, typeof(VerUtil.VersionReleaseLabelStruct));
+            this.IsNumeric = releaseLabel.fNumeric;
+            this.Value = releaseLabel.dwValue;
+            this.Label = VerUtil.VersionStringFromOffset(wzVersion, releaseLabel.cchLabelOffset, releaseLabel.cchLabel);
+        }
+
+        /// <summary>
+        /// Whether the label was parsed as a number.
+        /// </summary>
+        public bool IsNumeric { get; private set; }
+
+        /// <summary>
+        /// If <see cref="IsNumeric"/> then the value that was parsed.
+        /// </summary>
+        public uint Value { get; private set; }
+
+        /// <summary>
+        /// The string version of the label.
+        /// </summary>
+        public string Label { get; private set; }
+    }
+}
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/WixToolset.BootstrapperApplicationApi.csproj b/src/api/burn/WixToolset.BootstrapperApplicationApi/WixToolset.BootstrapperApplicationApi.csproj
new file mode 100644
index 00000000..2fe6d5bb
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/WixToolset.BootstrapperApplicationApi.csproj
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-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. -->
+
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFrameworks>netstandard2.0;net462</TargetFrameworks>
+    <AssemblyName>WixToolset.BootstrapperApplicationApi</AssemblyName>
+    <RootNamespace>WixToolset.BootstrapperApplicationApi</RootNamespace>
+    <DebugType>embedded</DebugType>
+    <Description>Managed Bootstrapper Application API</Description>
+    <NuspecFile>$(MSBuildThisFileName).nuspec</NuspecFile>
+    <CreateDocumentationFile>true</CreateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup Condition=" '$(NCrunch)'=='' ">
+    <ProjectReference Include="..\mbanative\mbanative.vcxproj" ReferenceOutputAssembly="false" PrivateAssets="All" Properties="Platform=x86" />
+  </ItemGroup>
+
+  <ItemGroup Condition=" '$(NCrunch)'=='' ">
+    <None Include="$(BaseOutputPath)$(Configuration)\$(PlatformToolset)\x86\mbanative.dll" CopyToOutputDirectory="PreserveNewest" />
+    <None Include="$(BaseOutputPath)$(Configuration)\$(PlatformToolset)\x86\mbanative.pdb" CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+  <ItemGroup Condition=" '$(NCrunch)'=='1' ">
+    <None Include="$(NCrunchOriginalProjectDir)..\..\build\$(SegmentName)\$(Configuration)\$(PlatformToolset)\x86\mbanative.dll" CopyToOutputDirectory="PreserveNewest" />
+    <None Include="$(NCrunchOriginalProjectDir)..\..\build\$(SegmentName)\$(Configuration)\$(PlatformToolset)\x86\mbanative.pdb" CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+</Project>
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/WixToolset.BootstrapperApplicationApi.nuspec b/src/api/burn/WixToolset.BootstrapperApplicationApi/WixToolset.BootstrapperApplicationApi.nuspec
new file mode 100644
index 00000000..22099635
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/WixToolset.BootstrapperApplicationApi.nuspec
@@ -0,0 +1,46 @@
+<?xml version="1.0"?>
+<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
+  <metadata minClientVersion="4.0">
+    <id>$id$</id>
+    <version>$version$</version>
+    <title>$title$</title>
+    <description>$description$</description>
+    <authors>$authors$</authors>
+    <icon>wix.png</icon>
+    <license type="expression">MS-RL</license>
+    <requireLicenseAcceptance>false</requireLicenseAcceptance>
+    <copyright>$copyright$</copyright>
+    <projectUrl>$projectUrl$</projectUrl>
+    <repository type="$repositorytype$" url="$repositoryurl$" commit="$repositorycommit$" />
+    <dependencies>
+      <group targetFramework=".NETFramework4.6.2" />
+      <group targetFramework=".NETStandard2.0" />
+      <group targetFramework="Native">
+        <dependency id="WixToolset.DUtil" version="[$version$,5)" />
+      </group>
+    </dependencies>
+  </metadata>
+
+  <files>
+    <file src="$projectFolder$\..\..\..\internal\images\wix.png" />
+
+    <file src="$projectFolder$\build\WixToolset.BootstrapperApplicationApi.props" target="build\" />
+
+    <file src="$projectFolder$\build\_._" target="lib\native" />
+    <file src="net462\$id$.dll" target="lib\net462" />
+    <file src="net462\$id$.xml" target="lib\net462" />
+    <file src="netstandard2.0\$id$.dll" target="lib\netstandard2.0" />
+    <file src="netstandard2.0\$id$.xml" target="lib\netstandard2.0" />
+
+    <file src="v143\ARM64\mbanative.dll" target="runtimes\win-arm64\native" />
+    <file src="v143\x64\mbanative.dll" target="runtimes\win-x64\native" />
+    <file src="v143\x86\mbanative.dll" target="runtimes\win-x86\native" />
+
+    <file src="$projectFolder$\..\balutil\inc\*" target="build\native\include" />
+    <file src="$projectFolder$\..\inc\BootstrapperApplication.h" target="build\native\include" />
+    <file src="$projectFolder$\..\inc\BootstrapperEngine.h" target="build\native\include" />
+    <file src="v141\x86\balutil.lib" target="build\native\v14\x86" />
+    <file src="v141\x64\balutil.lib" target="build\native\v14\x64" />
+    <file src="v141\ARM64\balutil.lib" target="build\native\v14\ARM64" />
+  </files>
+</package>
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/build/WixToolset.BootstrapperApplicationApi.props b/src/api/burn/WixToolset.BootstrapperApplicationApi/build/WixToolset.BootstrapperApplicationApi.props
new file mode 100644
index 00000000..b276574d
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/build/WixToolset.BootstrapperApplicationApi.props
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-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. -->
+
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <AdditionalIncludeDirectories>$(MSBuildThisFileDirectory)native\include\;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+    </ClCompile>
+    <ResourceCompile>
+      <AdditionalIncludeDirectories>$(MSBuildThisFileDirectory)native\include\;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+    </ResourceCompile>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition=" $(PlatformToolset.ToLower().StartsWith('v14')) ">
+    <Link>
+      <AdditionalDependencies>$(MSBuildThisFileDirectory)native\v14\$(PlatformTarget)\balutil.lib;%(AdditionalDependencies)</AdditionalDependencies>
+    </Link>
+  </ItemDefinitionGroup>
+</Project>
diff --git a/src/api/burn/WixToolset.BootstrapperApplicationApi/build/_._ b/src/api/burn/WixToolset.BootstrapperApplicationApi/build/_._
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/api/burn/WixToolset.BootstrapperApplicationApi/build/_._