1 files changed, 1 insertions, 1 deletions

diff --git a/src/wixext/DirectXExtensionFactory.cs b/src/wixext/DirectXExtensionFactory.cs
index b3755ee9..fb7f84aa 100644
--- a/src/wixext/DirectXExtensionFactory.cs
+++ b/src/wixext/DirectXExtensionFactory.cs
@@ -8,7 +8,7 @@ namespace WixToolset.DirectX
 
     public class DirectXExtensionFactory : BaseExtensionFactory
     {
-        protected override IEnumerable<Type> ExtensionTypes => new[]
+        protected override IReadOnlyCollection<Type> ExtensionTypes => new[]
         {
             typeof(DirectXExtensionData),
         };