diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index e70c8fd..2683e2d 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -12,7 +12,7 @@ jobs:
 
     strategy:
       matrix:
-        php: [8.1, 8.2, 8.3]
+        php: [8.1, 8.2, 8.3, 8.4]
         laravel: [10.*, 11.*]
         stability: [prefer-lowest, prefer-stable]
         os: [ubuntu-latest]
@@ -25,9 +25,15 @@ jobs:
             php: 8.3
             laravel: 11.*
             stability: prefer-stable
+          - os: windows-latest
+            php: 8.4
+            laravel: 11.*
+            stability: prefer-stable
         exclude:
           - php: 8.1
             laravel: 11.*
+          - php: 8.4
+            laravel: 10.*
 
     name: P${{ matrix.php }} - L${{ matrix.laravel }} - ${{ matrix.stability }} - ${{ matrix.os }}
 
@@ -48,7 +54,7 @@ jobs:
           composer update --${{ matrix.stability }} --prefer-dist --no-interaction --no-suggest
 
       - name: Execute tests
-        run: vendor/bin/phpunit
+        run: vendor/bin/phpunit --display-deprecation ${{ matrix.stability == 'prefer-stable' && '--fail-on-deprecation' || '' }}
 
       - name: Send Slack notification
         uses: 8398a7/action-slack@v2
diff --git a/composer.json b/composer.json
index 18a9366..95ba958 100644
--- a/composer.json
+++ b/composer.json
@@ -7,10 +7,10 @@
         "mustangostang/spyc": "dev-master#dfd9aadc1f5224065d55b42b712c7e99a50a3f4d"
     },
     "require-dev": {
-        "statamic/cms": "^5.0",
+        "statamic/cms": "dev-php84",
         "mockery/mockery": "^1.4.4",
-        "orchestra/testbench": "^8.0 || ^9.0",
-        "phpunit/phpunit": "^10.0"
+        "orchestra/testbench": "^8.28 || ^9.6.1",
+        "phpunit/phpunit": "^10.5.35"
     },
     "autoload": {
         "psr-4": {