1 files changed, 2 insertions, 0 deletions
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index a1d089ebac..266a0b835b 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -172,6 +172,8 @@ class VersionsRestServlet(RestServlet):
                     "org.matrix.msc4140": bool(self.config.server.max_event_delay_ms),
                     # Simplified sliding sync
                     "org.matrix.simplified_msc3575": msc3575_enabled,
+                    # Arbitrary key-value profile fields.
+                    "uk.tcpip.msc4133": self.config.experimental.msc4133_enabled,
                 },
             },
         )