diff --git a/CHANGES.md b/CHANGES.md
index 58fb9acdda..45d3cdb131 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,13 @@
+Synapse 0.33.5.1 (2018-09-25)
+=============================
+
+Internal Changes
+----------------
+
+- Fix incompatibility with older Twisted version in tests. Thanks 
+  @OlegGirko! ([\#3940](https://github.com/matrix-org/synapse/issues/3940))
+
+
 Synapse 0.33.5 (2018-09-24)
 ===========================
 
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 58244a5dd4..b1f7a89fba 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -27,4 +27,4 @@ try:
 except ImportError:
     pass
 
-__version__ = "0.33.5"
+__version__ = "0.33.5.1"
diff --git a/tests/http/test_fedclient.py b/tests/http/test_fedclient.py
index 66c09f63b6..f3cb1423f0 100644
--- a/tests/http/test_fedclient.py
+++ b/tests/http/test_fedclient.py
@@ -54,7 +54,7 @@ class FederationClientTests(HomeserverTestCase):
     def test_client_never_connect(self):
         """
         If the HTTP request is not connected and is timed out, it'll give a
-        ConnectingCancelledError.
+        ConnectingCancelledError or TimeoutError.
         """
         d = self.cl.get_json("testserv:8008", "foo/bar", timeout=10000)
 
@@ -76,7 +76,7 @@ class FederationClientTests(HomeserverTestCase):
         self.reactor.advance(10.5)
         f = self.failureResultOf(d)
 
-        self.assertIsInstance(f.value, ConnectingCancelledError)
+        self.assertIsInstance(f.value, (ConnectingCancelledError, TimeoutError))
 
     def test_client_connect_no_response(self):
         """