diff --git a/changelog.d/12020.feature b/changelog.d/12020.feature
new file mode 100644
index 0000000000000000000000000000000000000000..1ac9d2060e2a8598763ecabb6b8aefcf0e958b5f
--- /dev/null
+++ b/changelog.d/12020.feature
@@ -0,0 +1 @@
+Advertise Matrix 1.1 support on `/_matrix/client/versions`.
\ No newline at end of file
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index 2290c57c126e414302b64a8f0d725293dca83ca0..35b88e9bbf14b7f80da80f575c4f1f71a5d108a8 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -73,6 +73,7 @@ class VersionsRestServlet(RestServlet):
                     "r0.5.0",
                     "r0.6.0",
                     "r0.6.1",
+                    "v1.1",
                 ],
                 # as per MSC1497:
                 "unstable_features": {