diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index aa60125..bb4ccd6 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -14,11 +14,17 @@ on:
       - 'doc/**'
       - '**.md'
   workflow_dispatch: # Allow triggering manually
+    inputs:
+      core_ref:
+        description: Use a specific version of the core for the workflow run. Defaults to master.
+        type: string
+        default: 'master'
 jobs:
   wagon_tests:
     uses: hitobito/hitobito/.github/workflows/wagon-tests.yml@master
     with:
       wagon_repository: ${{ github.event.repository.name }}
+      core_ref: ${{ inputs.core_ref }}
     secrets:
       HEARTBEAT_URL: ${{ secrets.HEARTBEAT_URL }}
       HEARTBEAT_TOKEN: ${{ secrets.HEARTBEAT_TOKEN }}