2 files changed, 2 insertions, 2 deletions

diff --git a/src/wixext/HttpExtensionFactory.cs b/src/wixext/HttpExtensionFactory.cs
index fa23dac6..ad7d84d0 100644
--- a/src/wixext/HttpExtensionFactory.cs
+++ b/src/wixext/HttpExtensionFactory.cs
@@ -8,7 +8,7 @@ namespace WixToolset.Http
 
     public class HttpExtensionFactory : BaseExtensionFactory
     {
-        protected override IEnumerable<Type> ExtensionTypes => new[]
+        protected override IReadOnlyCollection<Type> ExtensionTypes => new[]
         {
             typeof(HttpCompiler),
             typeof(HttpExtensionData),
diff --git a/src/wixext/HttpWindowsInstallerBackendBinderExtension.cs b/src/wixext/HttpWindowsInstallerBackendBinderExtension.cs
index 7a94257b..8e4f1a96 100644
--- a/src/wixext/HttpWindowsInstallerBackendBinderExtension.cs
+++ b/src/wixext/HttpWindowsInstallerBackendBinderExtension.cs
@@ -8,6 +8,6 @@ namespace WixToolset.Http
 
     public class HttpWindowsInstallerBackendBinderExtension : BaseWindowsInstallerBackendBinderExtension
     {
-        public override IEnumerable<TableDefinition> TableDefinitions => HttpTableDefinitions.All;
+        public override IReadOnlyCollection<TableDefinition> TableDefinitions => HttpTableDefinitions.All;
     }
 }