diff --git a/pyproject.toml b/pyproject.toml
index 1cfba81..38541d9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,7 +2,7 @@
 requires = [
     "setuptools>=64",
     "setuptools_scm>=8",
-    "cython==0.29.14",
+    "cython==0.29.13",
     "cmake",
     "numpy>=1.25.0; python_version>='3.9'",
     "oldest-supported-numpy; python_version<'3.9'",