diff --git a/.github/workflows/mutation.yml b/.github/workflows/mutation.yml
index cbf8011e..e5b6e4a6 100644
--- a/.github/workflows/mutation.yml
+++ b/.github/workflows/mutation.yml
@@ -4,7 +4,7 @@ on:
   pull_request:
   push:
     branches:
-      - "1.x"
+      - "5.x"
   schedule:
     - cron:  '* 8 * * *'