diff --git a/.zuul.yaml b/.zuul.yaml
index dae11427..daa2e531 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -5,7 +5,9 @@
       Build documentation for openstackdocstheme with main branch of important
       libs. Takes advantage of the base tox job's install-siblings feature.
     # The job only tests the latest and shouldn't be run on the stable branches
-    branches: ^(?!stable)
+    branches:
+      regex: ^stable/.*$
+      negate: true
     required-projects:
       - name: github.com/sphinx-doc/sphinx
     vars: