diff --git a/setup.py b/setup.py
index 01a6c94..2c0ac3f 100644
--- a/setup.py
+++ b/setup.py
@@ -25,7 +25,7 @@
     'black >= 23,< 26',
     'build >= 0.10,< 1.5',
     'flake8 >= 6,< 8',
-    'isort >= 5,< 8',
+    'isort >= 5,< 9',
     'mypy >= 1.5,< 1.20',
     'pytest >= 7,< 10',
     'pytest-cov >= 4,< 8',