diff --git a/.github/workflows/test-make.yaml b/.github/workflows/test-make.yaml
index 66d940f0081..66169792dc4 100644
--- a/.github/workflows/test-make.yaml
+++ b/.github/workflows/test-make.yaml
@@ -15,19 +15,50 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
   cancel-in-progress: true
 jobs:
-  build-and-xref:
-    name: Build and Xref
-    strategy:
-      fail-fast: false
-      matrix:
-        erlang_version:
-        - '26'
-        - '27'
-        elixir_version:
-        - '1.17'
-    # @todo Add macOS and Windows.
+#  build-and-xref:
+#    name: Build and Xref
+#    strategy:
+#      fail-fast: false
+#      matrix:
+#        erlang_version:
+#        - '26'
+#        - '27'
+#        elixir_version:
+#        - '1.17'
+#    # @todo Add macOS and Windows.
+#    runs-on: ubuntu-latest
+#    timeout-minutes: 30
+#    steps:
+#    - name: CHECKOUT REPOSITORY
+#      uses: actions/checkout@v4
+#
+#    - name: FETCH TAGS
+#      run: git fetch --tags
+#
+#    - name: SETUP OTP & ELIXIR
+#      uses: erlef/setup-beam@v1.17
+#      with:
+#        otp-version: ${{ matrix.erlang_version }}
+#        elixir-version: ${{ matrix.elixir_version }}
+#        hexpm-mirrors: |
+#          https://builds.hex.pm
+#          https://cdn.jsdelivr.net/hex
+#
+#    - name: SANITY CHECK (rabbit)
+#      run: make -C deps/rabbit parallel-ct-sanity-check
+#
+#    - name: SANITY CHECK (rabbitmq_mqtt)
+#      run: make -C deps/rabbitmq_mqtt parallel-ct-sanity-check
+#
+#    - name: BUILD
+#      run: make
+#
+#    - name: XREF
+#      run: make xref
+
+  mixed-test:
+    name: Mixed version testing
     runs-on: ubuntu-latest
-    timeout-minutes: 30
     steps:
     - name: CHECKOUT REPOSITORY
       uses: actions/checkout@v4
@@ -38,53 +69,82 @@ jobs:
     - name: SETUP OTP & ELIXIR
       uses: erlef/setup-beam@v1.17
       with:
-        otp-version: ${{ matrix.erlang_version }}
-        elixir-version: ${{ matrix.elixir_version }}
+        otp-version: '27'
+        elixir-version: '1.17'
         hexpm-mirrors: |
           https://builds.hex.pm
           https://cdn.jsdelivr.net/hex
+        # This currently only applies to Elixir; and can be safely
+        # restricted to the build jobs to avoid duplication in output.
+        disable_problem_matchers: true
 
-    - name: SANITY CHECK (rabbit)
-      run: make -C deps/rabbit parallel-ct-sanity-check
+    - name: Download release signing keys
+      uses: dsaltares/fetch-gh-release-asset@master
+      with:
+        repo: rabbitmq/signing-keys
+        file: rabbitmq-release-signing-key.asc
 
-    - name: SANITY CHECK (rabbitmq_mqtt)
-      run: make -C deps/rabbitmq_mqtt parallel-ct-sanity-check
+    - name: Import release signing keys
+      run: gpg --import rabbitmq-release-signing-key.asc
 
-    - name: BUILD
-      run: make
+    - name: Download package generic unix
+      uses: dsaltares/fetch-gh-release-asset@master
+      with:
+        regex: true
+        file: "rabbitmq-server-generic-unix-[\\d.]*\\.tar.xz"
+        target: ./
 
-    - name: XREF
-      run: make xref
+    - name: Verify package
+      run: gpg --verify rabbitmq-server-generic-unix-*.asc rabbitmq-server-generic-unix-*.tar.xz
 
-  test:
-    name: Test
-    strategy:
-      fail-fast: false
-      matrix:
-        erlang_version:
-        - '26'
-#        - '27'
-        elixir_version:
-        - '1.17'
-        metadata_store:
-          - mnesia
-          - khepri
-    uses: ./.github/workflows/test-make-tests.yaml
-    with:
-      erlang_version: ${{ matrix.erlang_version }}
-      elixir_version: ${{ matrix.elixir_version }}
-      metadata_store: ${{ matrix.metadata_store }}
+    - name: Extract package generic unix
+      run: tar xf rabbitmq-server-generic-unix-*.tar.xz
 
-  type-check:
-    name: Type check
-    strategy:
-      fail-fast: false
-      matrix:
-        erlang_version: # Latest OTP
-        - '27'
-        elixir_version: # Latest Elixir
-        - '1.17'
-    uses: ./.github/workflows/test-make-type-check.yaml
-    with:
-      erlang_version: ${{ matrix.erlang_version }}
-      elixir_version: ${{ matrix.elixir_version }}
+    - run: ls -la
+
+    - name: RUN TESTS
+      run: |
+        make -C deps/rabbit ct-cluster_upgrade RABBITMQ_RUN_SECONDARY=rabbitmq-server-4.0.2/
+
+    - name: UPLOAD TEST LOGS
+      if: always()
+      uses: actions/upload-artifact@v4
+      with:
+        name: CT logs mixed
+        path: |
+          logs/
+#          !logs/**/log_private
+        if-no-files-found: ignore
+
+#  test:
+#    name: Test
+#    strategy:
+#      fail-fast: false
+#      matrix:
+#        erlang_version:
+#        - '26'
+##        - '27'
+#        elixir_version:
+#        - '1.17'
+#        metadata_store:
+#          - mnesia
+#          - khepri
+#    uses: ./.github/workflows/test-make-tests.yaml
+#    with:
+#      erlang_version: ${{ matrix.erlang_version }}
+#      elixir_version: ${{ matrix.elixir_version }}
+#      metadata_store: ${{ matrix.metadata_store }}
+#
+#  type-check:
+#    name: Type check
+#    strategy:
+#      fail-fast: false
+#      matrix:
+#        erlang_version: # Latest OTP
+#        - '27'
+#        elixir_version: # Latest Elixir
+#        - '1.17'
+#    uses: ./.github/workflows/test-make-type-check.yaml
+#    with:
+#      erlang_version: ${{ matrix.erlang_version }}
+#      elixir_version: ${{ matrix.elixir_version }}