diff --git a/.github/phpunit-matrix.js b/.github/phpunit-matrix.js
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/.github/workflows/test-old-branches.yml b/.github/workflows/test-old-branches.yml
index 952f10370e277..892cc3847d9e9 100644
--- a/.github/workflows/test-old-branches.yml
+++ b/.github/workflows/test-old-branches.yml
@@ -25,7 +25,7 @@ on:
 permissions: {}
 
 env:
-  CURRENTLY_SUPPORTED_BRANCH: '6.8'
+  CURRENTLY_SUPPORTED_BRANCH: '6.9'
 
 jobs:
   dispatch-workflows-for-old-branches:
diff --git a/.github/workflows/upgrade-develop-testing.yml b/.github/workflows/upgrade-develop-testing.yml
index b33188106c44f..91abd0cd05849 100644
--- a/.github/workflows/upgrade-develop-testing.yml
+++ b/.github/workflows/upgrade-develop-testing.yml
@@ -51,7 +51,15 @@ jobs:
     permissions:
       contents: read
 
-  # Run upgrade tests for the current branch.
+# Because the number of jobs spawned can quickly balloon out of control, the following methodology is applied when
+# building out the matrix below:
+#
+# - The two most recent releases of WordPress are always tested.
+# - After a branch is created, the pre-release version is also added.
+# - The oldest version of WordPress receiving security updates as a courtesy that also runs on a PHP version supported by trunk
+#   should always be tested.
+# - PHP and DB are kept to a minimum. In general this should be the highest and lowest supported versions of each with excludes being
+#   updated to keep the matrix as small as is reasonable.
   upgrade-tests-develop:
     name: Upgrade from ${{ matrix.wp }}
     uses: ./.github/workflows/reusable-upgrade-testing.yml
@@ -67,7 +75,7 @@ jobs:
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.4' ]
         # WordPress 5.3 is the oldest version that supports PHP 7.4.
-        wp: [ '5.3', '6.7', '6.8', '6.9-RC1' ]
+        wp: [ '5.3', '6.8', '6.9' ]
         multisite: [ false, true ]
     with:
       os: ${{ matrix.os }}
@@ -93,7 +101,7 @@ jobs:
         php: [ '7.4', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '8.4' ]
-        wp: [ '6.7', '6.8' ]
+        wp: [ '6.8', '6.9' ]
         multisite: [ false, true ]
     with:
       os: ${{ matrix.os }}
diff --git a/.github/workflows/upgrade-testing.yml b/.github/workflows/upgrade-testing.yml
index 4f6025e054580..a7a08a4a1f645 100644
--- a/.github/workflows/upgrade-testing.yml
+++ b/.github/workflows/upgrade-testing.yml
@@ -71,7 +71,7 @@ jobs:
         php: [ '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.0', '8.4', '9.5' ]
-        wp: [ '6.7', '6.8' ]
+        wp: [ '6.8', '6.9' ]
         multisite: [ false, true ]
     with:
       os: ${{ matrix.os }}