diff --git a/core/src/avm2/globals/flash/net/URLRequestDefaults.as b/core/src/avm2/globals/flash/net/URLRequestDefaults.as
index e3ae2d81f..32945bec3 100644
--- a/core/src/avm2/globals/flash/net/URLRequestDefaults.as
+++ b/core/src/avm2/globals/flash/net/URLRequestDefaults.as
@@ -9,6 +9,7 @@ package flash.net
     import __ruffle__.stub_getter;
     import __ruffle__.stub_setter;
 
+    [API("661")]
     public class URLRequestDefaults
     {
         // The default setting for the authenticate property of URLRequest objects.