1 files changed, 3 insertions, 0 deletions
diff --git a/synapse/rest/client/capabilities.py b/synapse/rest/client/capabilities.py
index 2a3e24ae7e..5c0e3a5680 100644
--- a/synapse/rest/client/capabilities.py
+++ b/synapse/rest/client/capabilities.py
@@ -73,6 +73,9 @@ class CapabilitiesRestServlet(RestServlet):
                 "enabled": self.config.registration.enable_3pid_changes
             }
 
+        if self.config.experimental.msc3440_enabled:
+            response["capabilities"]["io.element.thread"] = {"enabled": True}
+
         return 200, response