diff --git a/composer.json b/composer.json
index 7fc5100..9f68bac 100644
--- a/composer.json
+++ b/composer.json
@@ -28,7 +28,7 @@
         "silverstripe/vendor-plugin": "^2"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.6",
+        "phpunit/phpunit": "^11.3",
         "squizlabs/php_codesniffer": "^3.7",
         "silverstripe/asset-admin": "^3",
         "silverstripe/cms": "^6",
diff --git a/tests/php/CampaignAdminTest.php b/tests/php/CampaignAdminTest.php
index e092c8e..b81a375 100644
--- a/tests/php/CampaignAdminTest.php
+++ b/tests/php/CampaignAdminTest.php
@@ -137,7 +137,7 @@ public function testFilters()
         );
     }
 
-    public function readCampaignDataProvider()
+    public static function readCampaignDataProvider()
     {
         return [
             'valid campaign' => ['change1', 'CMS_ACCESS_CampaignAdmin', 200],
@@ -162,7 +162,7 @@ public function testReadCampaign(
         $this->assertEquals($expectedResponseCode, $response->getStatusCode());
     }
 
-    public function provideRemoveCampaignItem(): array
+    public static function provideRemoveCampaignItem(): array
     {
         return [
             'open campaign' => [false, false, 204],