diff --git a/pytest.ini b/pytest.ini
index 3dd2c766..ecf508ba 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,10 +1,11 @@
 [pytest]
 addopts = -p no:flask -p no:pytest_swh_storage
 norecursedirs = docs node_modules .tox
 DJANGO_SETTINGS_MODULE = swh.web.settings.tests
 filterwarnings =
     ignore:.*Plural value must be an integer, got float
     ignore:.*Using or importing the ABCs from 'collections'
     ignore:.*uses the 'client' fixture
     ignore:.*uses the 'mocker' fixture
     ignore:.*uses the 'requests_mock' fixture
+    ignore:.*'U' mode is deprecated