1 files changed, 3 insertions, 1 deletions
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index db09ff285f..6efd81f204 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -45,7 +45,9 @@ REQUIREMENTS = [
     "signedjson>=1.0.0",
     "pynacl>=1.2.1",
     "idna>=2",
-    "service_identity>=16.0.0",
+
+    # validating SSL certs for IP addresses requires service_identity 18.1.
+    "service_identity>=18.1.0",
 
     # our logcontext handling relies on the ability to cancel inlineCallbacks
     # (https://twistedmatrix.com/trac/ticket/4632) which landed in Twisted 18.7.