diff --git a/pyproject.toml b/pyproject.toml
index ec63234..037b94f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,7 +28,7 @@ dynamic = ["version"]
 [project.optional-dependencies]
 test = [
     "black==25.1.0",
-    "filelock==3.29.0",
+    "filelock==4.2.9",
     "flake8==7.3.0",
     "pyright==1.1.414",
     "pytest==8.4.1",