diff --git a/setup.cfg b/setup.cfg
index d610893..6c87d5f 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -36,7 +36,7 @@ tests =
   black
   pylint
   mypy
-  isort
+  isort<5,>=4.2.5
 
 [coverage:run]
 branch = True