diff --git a/.github/workflows/mt-build.yml b/.github/workflows/mt-build.yml
index 955d56d..dfdba33 100644
--- a/.github/workflows/mt-build.yml
+++ b/.github/workflows/mt-build.yml
@@ -9,120 +9,6 @@ on:
       # TODO 'develop', 'main'?
 # gh workflow run mt-build.yml --ref <branch>
 # gh run list --workflow=mt-build.yml
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref || github.head_ref }}
-  cancel-in-progress: true
-env:
-  MT_BRANCH_NAME: ${{ github.head_ref || github.ref_name }}
-  MT_TARGET_BRANCH_NAME: ${{ github.base_ref || github.ref_name }}
-  MT_SHA: ${{ github.event.pull_request.head.sha || github.sha }}
 jobs:
-  MT-BUILD-JOB:
-    name: "MT Build"
-    runs-on: ubuntu-latest
-    steps:
-
-      - name: MT select main repo checkout branch
-        id: mt-pick-main-repo-checkout-branch
-        env:
-          GH_TOKEN: ${{ github.token }} # GitHub CLI in a GitHub Actions workflow
-        run: |
-          REPOSITORY_OWNER_AND_NAME=${{ github.repository }};
-          REPOSITORY_NAME=$(basename $REPOSITORY_OWNER_AND_NAME);
-          if [ $REPOSITORY_OWNER_AND_NAME = "mtransitapps/mtransit-for-android" ]; then
-            CHECKOUT_BRANCH="" # defaults to the reference or SHA for that event
-          else
-            MAIN_REPO_URL="https://github.com/mtransitapps/mtransit-for-android.git"
-            BRANCH_EXISTS=$(git ls-remote --heads $MAIN_REPO_URL $MT_BRANCH_NAME | wc -l);
-            if [ $BRANCH_EXISTS -eq 1 ]; then
-              CHECKOUT_BRANCH=$MT_BRANCH_NAME
-            else
-              # Pull request target branch with same name?
-              BRANCH_EXISTS=$(git ls-remote --heads $MAIN_REPO_URL $MT_TARGET_BRANCH_NAME | wc -l);
-              if [ $BRANCH_EXISTS -eq 1 ]; then
-                CHECKOUT_BRANCH=$MT_TARGET_BRANCH_NAME
-              else
-                echo "WARNING: no match for current or target branch!!!"
-                DEFAULT_REPO_BRANCH=$(gh api repos/mtransitapps/mtransit-for-android --jq '.default_branch');
-                CHECKOUT_BRANCH=$DEFAULT_REPO_BRANCH
-              fi
-            fi
-          fi
-          echo "Checkout branch: '$CHECKOUT_BRANCH'."
-          echo "mt_checkout_branch=$CHECKOUT_BRANCH" >> "$GITHUB_OUTPUT"
-
-      - name: MT check out main repo
-        uses: actions/checkout@v5
-        with:
-          repository: mtransitapps/mtransit-for-android
-          ref: ${{ steps.mt-pick-main-repo-checkout-branch.outputs.mt_checkout_branch }}
-          submodules: true # required to set right token
-          fetch-depth: 0 # fetch all (not required util release build)
-      - name: MT check out submodules
-        run: ./checkout_submodules.sh
-      - name: MT check out all git submodule closest branch
-        if: github.event_name == 'pull_request'
-        run: |
-          echo "Checking out submodules closest branch, '$MT_BRANCH_NAME' or '$MT_TARGET_BRANCH_NAME':"
-          git submodule foreach 'git checkout $MT_BRANCH_NAME || git checkout $MT_TARGET_BRANCH_NAME'
-          echo "Showing submodules current branch:"
-          git submodule foreach 'git branch --show-current'
-
-      - name: MT check out this module repo build SHA
-        if: github.repository != 'mtransitapps/mtransit-for-android'
-        run: |
-          REPOSITORY_OWNER_AND_NAME=${{ github.repository }};
-          REPOSITORY_NAME=$(basename $REPOSITORY_OWNER_AND_NAME);
-          echo "Checking our this repo '$REPOSITORY_NAME' workflow sha '$MT_SHA':"
-          git -C $REPOSITORY_NAME checkout $MT_SHA;
-
-      - name: MT setup MT_GIT_BRANCH env
-        if: github.repository == 'mtransitapps/mtransit-for-android' || github.event_name != 'pull_request'
-        run: |
-          # MT_GIT_BRANCH=${GITHUB_REF##*/}"
-          MT_GIT_BRANCH=${{ github.head_ref || github.ref_name }}
-          # echo "MT_GIT_BRANCH=${GITHUB_REF##*/}" >> $GITHUB_ENV
-          echo "MT_GIT_BRANCH=$MT_GIT_BRANCH" >> $GITHUB_ENV
-
-      - name: MT code setup
-        run: ./commons/code_setup.sh
-      - name: MT set up JDK 17
-        uses: actions/setup-java@v5
-        with:
-          distribution: 'zulu'
-          java-version: '17'
-      - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v5
-
-      - name: MT test
-        run: ./test.sh
-      - name: MT artifact > unit tests XML results
-        uses: actions/upload-artifact@v5
-        if: ${{ always() }} # even if tests fails
-        with:
-          name: unit-test-xml-results
-          path: |
-            */build/test-results/**/*.xml
-            */build/test-results/*.xml
-            */build/reports/*.xml
-      - name: MT artifact > HTML reports
-        uses: actions/upload-artifact@v5
-        if: ${{ always() }} # even if tests fails
-        with:
-          name: html-reports
-          path: |
-            */build/reports/
-            !**/*.xml
-
-      - name: MT assemble release (APK & ABB)
-        if: github.event_name != 'pull_request'
-        run: ./assemble_release.sh
-        env:
-          MT_ENCRYPT_KEY: ${{ secrets.MT_ENCRYPT_KEY }}
-      - name: MT artifact > app-android > APK & ABB
-        uses: actions/upload-artifact@v5
-        with:
-          name: app-android-apk-bundle
-          path: |
-            app-android/build/outputs/apk
-            app-android/build/outputs/bundle
+  MT-MAIN-REPO-BUILD-JOB:
+    uses: mtransitapps/mtransit-for-android/.github/workflows/mt-build.yml@master