diff --git a/.github/workflows/merge-up.yml b/.github/workflows/merge-up.yml
index cb5a3df02..03f3065bb 100644
--- a/.github/workflows/merge-up.yml
+++ b/.github/workflows/merge-up.yml
@@ -28,5 +28,5 @@ jobs:
         with:
           ref: ${{ github.ref_name }}
           branchNamePattern: 'v<major>.<minor>'
-          fallbackBranch: 'master'
+          devBranchNamePattern: 'v<major>.x'
           enableAutoMerge: true