1 files changed, 5 insertions, 0 deletions
diff --git a/synapse/rest/client/capabilities.py b/synapse/rest/client/capabilities.py
index 4237071c61..e84dde31b1 100644
--- a/synapse/rest/client/capabilities.py
+++ b/synapse/rest/client/capabilities.py
@@ -77,6 +77,11 @@ class CapabilitiesRestServlet(RestServlet):
                 "enabled": True,
             }
 
+        if self.config.experimental.msc3664_enabled:
+            response["capabilities"]["im.nheko.msc3664.related_event_match"] = {
+                "enabled": self.config.experimental.msc3664_enabled,
+            }
+
         return HTTPStatus.OK, response