1 files changed, 1 insertions, 0 deletions
diff --git a/setup.py b/setup.py
index 553e7b2..57b2b5a 100644
--- a/setup.py
+++ b/setup.py
@@ -17,6 +17,7 @@ requirements = [
 ]
 
 extras_require = {
+    ':python_version < "3.5"': 'backports.ssl_match_hostname >= 3.5',
     # While not imported explicitly, the ipaddress module is required for
     # ssl_match_hostname to verify hosts match with certificates via
     # ServerAltname: https://pypi.python.org/pypi/backports.ssl_match_hostname