diff --git a/pyproject.toml b/pyproject.toml
index e89f2a265..4aaa99e3b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -108,7 +108,7 @@ tests = [
     # and, protected method calls in our tests
     "pylint-plugin-utils==0.7",
     # type-checking
-    "mypy==0.990",
+    "mypy==0.991",
     "types-requests",
     "types-tabulate",
     "types-toml",