diff --git a/setup.cfg b/setup.cfg
index 60de1d9..8fe5844 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -85,7 +85,7 @@ dev =
     pre-commit~=2.20.0
     sphinx==3.2.1
     sphinxcontrib-napoleon~=0.7
-    tox~=3.28.0
+    tox>=3.28,<4.24
     flask_testing~=0.8.0
     sphinx-rtd-theme~=0.5.0
     sphinx-argparse~=0.2.5