1 files changed, 1 insertions, 1 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),