diff --git a/pyproject.toml b/pyproject.toml
index 2490f2ff..f0a66fe4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -58,7 +58,7 @@ dependencies = [
 dev = [
     "certifi",
     "coverage",
-    "mypy<1.20",
+    "mypy<1.21",
     "pytest<10",
     "pytz",
     "ruff<0.16",