diff --git a/pyproject.toml b/pyproject.toml
index 5be9909..0f782eb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -47,7 +47,7 @@ dev = [
   "coverage >=7.5.0",
   "coveralls >=4.0.1",
   "mypy",
-  "numpydoc >=1.8.0; python_version >=3.9",
+  "numpydoc >=1.8.0; python_version >='3.9'",
   "pytest >=8.3.2",
   "pytest-cov >=5.0.0",
   "black ==24.8.0",