diff --git a/pyproject.toml b/pyproject.toml
index 243ddbb..8a3c9b3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -68,7 +68,7 @@ dev = [
     "pre-commit~=3.8.0",
     "mypy~=1.11.2",
     "ruff~=0.6.5",
-    "tox>=4.18.1,<4.21.0"
+    "tox>=4.18.1,<4.22.0"
 ]
 
 [project.scripts]