1 files changed, 1 insertions, 0 deletions
diff --git a/synapse/api/events/__init__.py b/synapse/api/events/__init__.py
index 921fd08832..aa04dbece7 100644
--- a/synapse/api/events/__init__.py
+++ b/synapse/api/events/__init__.py
@@ -51,6 +51,7 @@ class SynapseEvent(JsonEncodedObject):
         "depth",
         "destinations",
         "origin",
+        "outlier",
     ]
 
     required_keys = [