diff --git a/requirements.txt b/requirements.txt
index 5411efad1..bfaf05b5e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 certifi>=14.05.14 # MPL
 six>=1.9.0  # MIT
-python-dateutil>=2.5.3  # BSD
+python-dateutil>=2.9.0.post0  # BSD
 setuptools>=21.0.0  # PSF/ZPL
 pyyaml>=5.4.1  # MIT
 google-auth>=1.0.1  # Apache-2.0