1 files changed, 3 insertions, 1 deletions
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index 874869dc2d..1cfac87606 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -4,7 +4,7 @@
 # Copyright 2019 The Matrix.org Foundation C.I.C.
 # Copyright 2017 Vector Creations Ltd
 # Copyright 2016 OpenMarket Ltd
-# Copyright (C) 2023 New Vector, Ltd
+# Copyright (C) 2023-2024 New Vector, Ltd
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
@@ -171,6 +171,8 @@ class VersionsRestServlet(RestServlet):
                             is not None
                         )
                     ),
+                    # MSC4140: Delayed events
+                    "org.matrix.msc4140": True,
                     # MSC4151: Report room API (Client-Server API)
                     "org.matrix.msc4151": self.config.experimental.msc4151_enabled,
                     # Simplified sliding sync