diff --git a/.forgejo/workflows/build.yaml b/.forgejo/workflows/build.yaml
index 853fe02..0b6fad1 100644
--- a/.forgejo/workflows/build.yaml
+++ b/.forgejo/workflows/build.yaml
@@ -11,6 +11,7 @@ jobs:
       PUSHED: ${{ github.event_name == 'push' }}
       REGISTRY: git.korhonen.cc
       REPO: ${{ env.REGISTRY }}/functionalhacker/forgejo-asciidoc
+      UPSTREAM: docker://codeberg.org/forgejo/forgejo
     runs-on: docker
     steps:
       - name: Check if update available
@@ -18,7 +19,7 @@ jobs:
         id: check
         uses: https://github.com/ClementTsang/docker-check-base-image-diff@v0.0.2
         with:
-          base-image: docker://codeberg.org/forgejo/forgejo:${{ env.FORGEJO_VERSION }}
+          base-image: ${{ env.UPSTREAM }}:${{ env.FORGEJO_VERSION }}
           derived-image: docker://${{ env.REPO }}:latest
       - name: Check result
         if: env.SCHEDULED == 'true'
@@ -37,7 +38,7 @@ jobs:
         id: point_release
         if: env.PUSHED == 'true' || steps.check.outputs.differs == 'true'
         run: |
-          VERSION="$(skopeo list-tags docker://codeberg.org/forgejo/forgejo | jq -r '.Tags | last' | cut -d '-' -f 1)"
+          VERSION="$(skopeo list-tags ${{ env.UPSTREAM }} | jq -r '.Tags | last' | cut -d '-' -f 1)"
           echo "Point release: $VERSION"
           echo "version=$VERSION" >> $GITHUB_OUTPUT
       - name: Build and push image