diff --git a/.github/workflows/test-old-branches.yml b/.github/workflows/test-old-branches.yml
index 9626a4971d..f0be35a208 100644
--- a/.github/workflows/test-old-branches.yml
+++ b/.github/workflows/test-old-branches.yml
@@ -28,12 +28,15 @@ jobs:
             'test-npm.yml'
         ]
         branch: [
+            '6.0',
             '5.9', '5.8', '5.7', '5.6', '5.5', '5.4', '5.3', '5.2', '5.1', '5.0',
             '4.9', '4.8', '4.7', '4.6', '4.5', '4.4', '4.3', '4.2', '4.1', '4.0',
             '3.9', '3.8', '3.7'
         ]
         include:
           # PHP Compatibility testing was introduced in 5.5.
+          - branch: '6.0'
+            workflow: 'php-compatibility.yml'
           - branch: '5.9'
             workflow: 'php-compatibility.yml'
           - branch: '5.8'
@@ -48,6 +51,8 @@ jobs:
           # End-to-end testing was introduced in 5.3 but was later removed as there were no meaningful assertions.
           # Starting in 5.8 with #52905, some additional tests with real assertions were introduced.
           # Branches 5.8 and newer should be tested to confirm no regressions are introduced.
+          - branch: '6.0'
+            workflow: 'end-to-end-tests.yml'
           - branch: '5.9'
             workflow: 'end-to-end-tests.yml'
           - branch: '5.8'
@@ -63,7 +68,7 @@ jobs:
     steps:
       - name: Dispatch workflow run
         uses: actions/github-script@9ac08808f993958e9de277fe43a64532a609130e # v6.0.0
-        if: ${{ github.event_name == 'push' || github.event.schedule == '0 0 15 * *' || matrix.branch == '5.9' }}
+        if: ${{ github.event_name == 'push' || github.event.schedule == '0 0 15 * *' || matrix.branch == '6.0' }}
         with:
           github-token: ${{ secrets.GHA_OLD_BRANCH_DISPATCH }}
           script: |