diff --git a/pyproject.toml b/pyproject.toml
index 831e602..7e382e5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -61,7 +61,7 @@ check = [
     "flake8<6",
     "flake8-black",
     "flake8-colors",
-    "flake8-isort>=4.2.0,<5.0.0",
+    "flake8-isort>=4.2.0,<6.0.0",
     "flake8-pyi",
     "flake8-typing-imports",
     "docutils",