diff --git a/composer.json b/composer.json
index 7ea9ded..f461963 100644
--- a/composer.json
+++ b/composer.json
@@ -27,7 +27,7 @@
         "guzzlehttp/guzzle": "^7.5"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.6",
+        "phpunit/phpunit": "^11.3",
         "squizlabs/php_codesniffer": "^3",
         "symfony/thanks": "^1.2",
         "silverstripe/standards": "^1",
diff --git a/tests/Forms/GridFieldRefreshButtonTest.php b/tests/Forms/GridFieldRefreshButtonTest.php
index 34eb563..8441f22 100644
--- a/tests/Forms/GridFieldRefreshButtonTest.php
+++ b/tests/Forms/GridFieldRefreshButtonTest.php
@@ -118,13 +118,13 @@ protected function getGridFieldMock()
         $gridFieldMock = $this
             ->getMockBuilder(GridField::class)
             ->setConstructorArgs(['TestGridField'])
-            ->setMethods(['Link'])
+            ->onlyMethods(['Link'])
             ->getMock();
 
         $gridFieldMock
             ->expects($this->any())
             ->method('Link')
-            ->will($this->returnValue('http://example.com'));
+            ->willReturn('http://example.com');
 
         return $gridFieldMock;
     }
diff --git a/tests/Model/PackageTest.php b/tests/Model/PackageTest.php
index 4392c07..70f8a3b 100644
--- a/tests/Model/PackageTest.php
+++ b/tests/Model/PackageTest.php
@@ -6,10 +6,11 @@
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\View\ArrayData;
+use PHPUnit\Framework\Attributes\DataProvider;
 
 class PackageTest extends SapphireTest
 {
-    public function providePackageNamesAndTitles()
+    public static function providePackageNamesAndTitles()
     {
         return [
             ['pretendvendor/silverstripe-prefixedpackage', 'prefixedpackage'],
@@ -26,10 +27,10 @@ public function providePackageNamesAndTitles()
     }
 
     /**
-     * @dataProvider providePackageNamesAndTitles
      *
      * Ensure the vendor and 'silverstripe-' is stripped from module names.
      */
+    #[DataProvider('providePackageNamesAndTitles')]
     public function testTitleFormatsNameCorrectly($name, $title)
     {
         $testPackage = new Package([
diff --git a/tests/Tasks/UpdatePackageInfoTest.php b/tests/Tasks/UpdatePackageInfoTest.php
index cdb11a1..2c7360f 100644
--- a/tests/Tasks/UpdatePackageInfoTest.php
+++ b/tests/Tasks/UpdatePackageInfoTest.php
@@ -60,8 +60,8 @@ public function getModuleVersion(string $module): string
         };
         Injector::inst()->registerService(new $mockVersionProvider(), VersionProvider::class);
         $composerLoader = $this->getMockBuilder(ComposerLoader::class)
-            ->setMethods(['getLock'])->getMock();
-        $composerLoader->expects($this->any())->method('getLock')->will($this->returnValue(json_decode(<<<LOCK
+            ->onlyMethods(['getLock'])->getMock();
+        $composerLoader->expects($this->any())->method('getLock')->willReturn(json_decode(<<<LOCK
 {
     "packages": [
         {
@@ -78,7 +78,7 @@ public function getModuleVersion(string $module): string
     "packages-dev": null
 }
 LOCK
-        )));
+        ));
 
         $task = UpdatePackageInfoTask::create();
         $task->setComposerLoader($composerLoader);
diff --git a/tests/Util/ApiLoaderTest.php b/tests/Util/ApiLoaderTest.php
index 2bf1043..6323cea 100644
--- a/tests/Util/ApiLoaderTest.php
+++ b/tests/Util/ApiLoaderTest.php
@@ -11,6 +11,7 @@
 use SilverStripe\Dev\SapphireTest;
 use Psr\SimpleCache\CacheInterface;
 use ReflectionMethod;
+use PHPUnit\Framework\Attributes\DataProvider;
 
 class ApiLoaderTest extends SapphireTest
 {
@@ -68,11 +69,11 @@ public function testCacheControlSettingsAreRespected()
     {
         $cacheMock = $this->getMockCacheInterface();
 
-        $cacheMock->expects($this->once())->method('get')->will($this->returnValue(false));
+        $cacheMock->expects($this->once())->method('get')->willReturn(false);
         $cacheMock->expects($this->once())
             ->method('set')
             ->with($this->anything(), '["foo\/bar","bin\/baz"]', 5000)
-            ->will($this->returnValue(true));
+            ->willReturn(true);
 
         $loader = $this->getLoader($cacheMock);
         $loader->setGuzzleClient($this->getMockClient(new Response(
@@ -90,10 +91,10 @@ public function testCachedAddonsAreUsedWhenAvailable()
     {
         $cacheMock = $this->getMockCacheInterface();
 
-        $cacheMock->expects($this->once())->method('get')->will($this->returnValue(json_encode($this->getFakeJson())));
+        $cacheMock->expects($this->once())->method('get')->willReturn(json_encode($this->getFakeJson()));
         $loader = $this->getLoader($cacheMock);
 
-        $mockClient = $this->getMockBuilder(Client::class)->setMethods(['send'])->getMock();
+        $mockClient = $this->getMockBuilder(Client::class)->onlyMethods(['send'])->getMock();
         $mockClient->expects($this->never())->method('send');
         $loader->setGuzzleClient($mockClient);
 
@@ -104,9 +105,7 @@ public function testCachedAddonsAreUsedWhenAvailable()
         $this->assertSame($this->getFakeJson(), $addons);
     }
 
-    /**
-     * @dataProvider provideParseResponseContentsEmpty
-     */
+    #[DataProvider('provideParseResponseContentsEmpty')]
     public function testParseResponseContentsEmpty(string $contents)
     {
         // ApiLoader is an abstract class
@@ -125,7 +124,7 @@ protected function getCacheKey()
         $inst->parseResponseContents($contents, $failureMessage);
     }
 
-    public function provideParseResponseContentsEmpty(): array
+    public static function provideParseResponseContentsEmpty(): array
     {
         return [
             [
@@ -179,15 +178,15 @@ protected function getLoader($cacheMock = false)
         if (!$cacheMock) {
             $cacheMock = $this->getMockCacheInterface();
 
-            $cacheMock->expects($this->any())->method('get')->will($this->returnValue(false));
-            $cacheMock->expects($this->any())->method('set')->will($this->returnValue(true));
+            $cacheMock->expects($this->any())->method('get')->willReturn(false);
+            $cacheMock->expects($this->any())->method('set')->willReturn(true);
         }
 
         $loader = $this->getMockBuilder(ApiLoader::class)
             ->getMockForAbstractClass();
 
         $loader->setCache($cacheMock);
-        $loader->expects($this->any())->method('getCacheKey')->will($this->returnValue('cacheKey'));
+        $loader->expects($this->any())->method('getCacheKey')->willReturn('cacheKey');
 
         return $loader;
     }
diff --git a/tests/Util/ModuleHealthLoaderTest.php b/tests/Util/ModuleHealthLoaderTest.php
index c6ed3df..06722b9 100644
--- a/tests/Util/ModuleHealthLoaderTest.php
+++ b/tests/Util/ModuleHealthLoaderTest.php
@@ -15,7 +15,7 @@ protected function setUp(): void
         parent::setUp();
 
         $this->loader = $this->getMockBuilder(ModuleHealthLoader::class)
-            ->setMethods(['doRequest'])
+            ->onlyMethods(['doRequest'])
             ->getMock();
     }
 
diff --git a/tests/Util/SupportedAddonsLoaderTest.php b/tests/Util/SupportedAddonsLoaderTest.php
index 413544f..36464e6 100644
--- a/tests/Util/SupportedAddonsLoaderTest.php
+++ b/tests/Util/SupportedAddonsLoaderTest.php
@@ -17,7 +17,7 @@ protected function setUp(): void
         parent::setUp();
 
         $this->loader = $this->getMockBuilder(SupportedAddonsLoader::class)
-            ->setMethods(['doRequest'])
+            ->onlyMethods(['doRequest'])
             ->getMock();
     }