diff --git a/pyproject.toml b/pyproject.toml
index 68cbdca..a9b3e48 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -85,7 +85,7 @@ optional-dependencies.develop = [
   "mypy<2",
   "poethepoet<1",
   "pyproject-fmt>=1.3,<2.6",
-  "ruff<0.8",
+  "ruff<0.9",
   "validate-pyproject<0.23",
 ]
 optional-dependencies.fileio = [