diff --git a/.github/workflows/phpunit-tests-8.yml b/.github/workflows/phpunit-tests-8.yml
index 7f913b6..fbdb1f9 100644
--- a/.github/workflows/phpunit-tests-8.yml
+++ b/.github/workflows/phpunit-tests-8.yml
@@ -29,8 +29,8 @@ jobs:
           --health-retries=3
     strategy:
       matrix:
-        php-versions: [ '8.2', '8.1', '8.0' ]
-        wordpress-versions: [ '6.2', '6.1', '6.0' ]
+        php-versions: [ '8.3', '8.2' ]
+        wordpress-versions: [ '6.5', '6.4', '6.3' ]
         operating-system: [ ubuntu-20.04 ]
     env:
       UTMDC_BITLY_API: ${{secrets.UTMDC_BITLY_API}}
diff --git a/.github/workflows/phpunit-tests-legacy-8.yml b/.github/workflows/phpunit-tests-legacy-8.yml
new file mode 100644
index 0000000..087fc2d
--- /dev/null
+++ b/.github/workflows/phpunit-tests-legacy-8.yml
@@ -0,0 +1,78 @@
+name: PHPUnit Tests (8.x)
+
+on:
+  push:
+    branches:
+      - main
+      - development
+  pull_request:
+    branches:
+    types: [closed]
+  schedule:
+    - cron: '0 0 * * 0'
+
+jobs:
+  test-php:
+    name: WordPress ${{ matrix.wordpress-versions }} - PHP ${{ matrix.php-versions }} on ${{ matrix.operating-system }}
+    runs-on: ${{ matrix.operating-system }}
+    services:
+      mysql-service:
+        image: mysql:8.0
+        env:
+          MYSQL_ROOT_PASSWORD: root
+        ports:
+          - 3306
+        options: >-
+          --health-cmd="mysqladmin ping"
+          --health-interval=10s
+          --health-timeout=5s
+          --health-retries=3
+    strategy:
+      matrix:
+        php-versions: [ '8.1', '8.0' ]
+        wordpress-versions: [ '6.2', '6.1', '6.0' ]
+        operating-system: [ ubuntu-20.04 ]
+    env:
+      UTMDC_BITLY_API: ${{secrets.UTMDC_BITLY_API}}
+      UTMDC_REBRANDLY_API: ${{secrets.UTMDC_REBRANDLY_API}}
+      UTMDC_PLUGIN_DIR: ${{secrets.UTMDC_PLUGIN_DIR}}
+
+    steps:
+      - name: Start MySQL
+        run: sudo /etc/init.d/mysql start
+
+      - name: Setup PHP
+        # Commit hash for v2.25.4: https://github.com/shivammathur/setup-php/releases/tag/2.25.4
+        uses: shivammathur/setup-php@4bd44f22a98a19e0950cbad5f31095157cc9621b
+        with:
+          php-version: ${{ matrix.php-versions }}
+          extensions: mbstring
+          ini-values: post_max_size=256M, max_execution_time=180
+          coverage: xdebug
+
+      - name: Log Debug Information
+        run: |
+          echo "$GITHUB_REF"
+          echo "$GITHUB_EVENT_NAME"
+          php --version
+          mysql --version
+          lsb_release -a
+
+      - name: Checkout utm.codes
+        # Commit hash for v3.5.3: https://github.com/actions/checkout/releases/tag/v3.5.3
+        uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9
+        with:
+          fetch-depth: 0
+
+      - name: Install PHPUnit
+        run: |
+          composer require phpunit/phpunit:^9.5 --update-with-dependencies
+
+      - name: Install WordPress
+        run: |
+          bash _test/bin/install-wp-tests.sh wordpress_test root root localhost:3306 ${{ matrix.wordpress-versions }}
+
+      - name: Run PHPUnit Tests
+        run: |
+          cd _test
+          ../vendor/bin/phpunit