diff --git a/pyproject.toml b/pyproject.toml
index be9dcc7..e8b14b4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -32,7 +32,7 @@ dependencies = [
 
 [project.optional-dependencies]
 dev = [
-    "mypy>=0.991,<1.0",
+    "mypy>=0.991,<2.0",
 ]
 
 [project.urls]