diff --git a/pyproject.toml b/pyproject.toml
index 72f5f7a..c433723 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -50,7 +50,7 @@ flake8-comprehensions = "^3.8.0"
 flake8-docstrings = "^1.6.0"
 flake8-eradicate = "^1.2.0"
 flake8-markdown = "^0.3.0"
-flake8-simplify = "^0.19.2"
+flake8-simplify = ">=0.19.2,<0.21.0"
 mypy = ">=0.991,<1.2"
 pre-commit = ">=2.17,<4.0"
 pre-commit-hooks = "^4.1.0"