1 files changed, 5 insertions, 1 deletions
diff --git a/tox.ini b/tox.ini
index 297136fcc5..1a3489344f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -24,7 +24,8 @@ deps =
     # install the "enum34" dependency of cryptography.
     pip>=10
 
-# directories/files we run the linters on
+# directories/files we run the linters on.
+# if you update this list, make sure to do the same in scripts-dev/lint.sh
 lint_targets =
     setup.py
     synapse
@@ -103,6 +104,9 @@ usedevelop=true
 [testenv:py35-old]
 skip_install=True
 deps =
+    # Ensure a version of setuptools that supports Python 3.5 is installed.
+    setuptools < 51.0.0
+
     # Old automat version for Twisted
     Automat == 0.3.0