diff --git a/sytest-whitelist b/sytest-whitelist
index efc97b5e6..d84a0c2df 100644
--- a/sytest-whitelist
+++ b/sytest-whitelist
@@ -230,3 +230,4 @@ Push rules come down in an initial /sync
 Regular users can add and delete aliases in the default room configuration
 Regular users can add and delete aliases when m.room.aliases is restricted
 GET /r0/capabilities is not public
+Outbound federation can backfill events