diff --git a/setup.py b/setup.py
index 1038fffc..4731c86a 100644
--- a/setup.py
+++ b/setup.py
@@ -49,7 +49,7 @@
         "qa": [
             "black>=25.1,<26.6",
             "flake8~=7.3.0",
-            "isort>=6.0.1,<8.1.0",
+            "isort>=6.0.1,<9.1.0",
             "coverage>=7.10.0,<7.17.0",
             "tblib~=3.2.2",
             "docstrfmt>=2.0.0,<2.3.0",