diff --git a/demos/_unit-test/fatal-error.php b/demos/_unit-test/fatal-error.php
index e60d7214f4..cd157ed516 100644
--- a/demos/_unit-test/fatal-error.php
+++ b/demos/_unit-test/fatal-error.php
@@ -11,14 +11,10 @@
 
 $runOnShutdownFx = static function (\Closure $fx) use ($app) {
     // relies on https://github.com/atk4/ui/blob/5.0.0/src/App.php#L1108
-    $app->onHook(App::HOOK_BEFORE_RENDER, static function () use (&$fx) {
-        if ($fx !== null) {
-            try {
-                $fx();
-            } finally {
-                $fx = null;
-            }
-        }
+    $hookIndex = $app->onHook(App::HOOK_BEFORE_RENDER, static function () use ($app, &$hookIndex, $fx) {
+        $app->removeHook(App::HOOK_BEFORE_RENDER, $hookIndex, true);
+
+        $fx();
     });
 };
 
diff --git a/src/HtmlTemplate/Value.php b/src/HtmlTemplate/Value.php
index 3404552fa8..b930952412 100644
--- a/src/HtmlTemplate/Value.php
+++ b/src/HtmlTemplate/Value.php
@@ -25,7 +25,7 @@ private function encodeValueToHtml(string $value): string
      */
     public function set(string $value): self
     {
-        if (\PHP_MAJOR_VERSION === 7 || (\PHP_MAJOR_VERSION === 8 && \PHP_MAJOR_VERSION <= 1) // @phpstan-ignore-line
+        if (\PHP_VERSION_ID < 80200
                 ? !preg_match('~~u', $value) // much faster in PHP 8.1 and lower
                 : !mb_check_encoding($value, 'UTF-8')
         ) {
diff --git a/tests/AppTest.php b/tests/AppTest.php
index b0912fb6de..ef29b10f6c 100644
--- a/tests/AppTest.php
+++ b/tests/AppTest.php
@@ -9,6 +9,7 @@
 use Atk4\Ui\Exception\LateOutputError;
 use Atk4\Ui\HtmlTemplate;
 use Nyholm\Psr7\Factory\Psr17Factory;
+use PHPUnit\Framework\Attributes\DataProvider;
 
 class AppTest extends TestCase
 {
@@ -186,6 +187,7 @@ public static function provideUrlCases(): iterable
      * @param array<0|string, string|int|false> $page
      * @param array<string, string>             $extraRequestUrlArgs
      */
+    #[DataProvider('provideUrlCases')]
     public function testUrl(string $requestUrl, array $appStickyGetArguments, array $page, array $extraRequestUrlArgs, string $expectedUrl): void
     {
         $request = (new Psr17Factory())->createServerRequest('GET', $requestUrl);
diff --git a/tests/ButtonTest.php b/tests/ButtonTest.php
index 3c4f3cffd4..0bf5cca488 100644
--- a/tests/ButtonTest.php
+++ b/tests/ButtonTest.php
@@ -6,6 +6,7 @@
 
 use Atk4\Core\Phpunit\TestCase;
 use Atk4\Ui\Button;
+use PHPUnit\Framework\Attributes\DoesNotPerformAssertions;
 
 class ButtonTest extends TestCase
 {
@@ -14,6 +15,7 @@ class ButtonTest extends TestCase
     /**
      * @doesNotPerformAssertions
      */
+    #[DoesNotPerformAssertions]
     public function testButtonIcon(): void
     {
         $button = new Button(['Load', 'icon' => 'pause']);
diff --git a/tests/DemosHttpNoExitTest.php b/tests/DemosHttpNoExitTest.php
index 5059d613a0..b569a8084e 100644
--- a/tests/DemosHttpNoExitTest.php
+++ b/tests/DemosHttpNoExitTest.php
@@ -4,11 +4,14 @@
 
 namespace Atk4\Ui\Tests;
 
+use PHPUnit\Framework\Attributes\Group;
+
 /**
  * Same as DemosHttpTest, only App::callExit is set to false.
  *
  * @group demos_http
  */
+#[Group('demos_http')]
 class DemosHttpNoExitTest extends DemosHttpTest
 {
     /** @var bool set the app->callExit in demo */
diff --git a/tests/DemosHttpTest.php b/tests/DemosHttpTest.php
index 738f07852d..9cb13dc52c 100644
--- a/tests/DemosHttpTest.php
+++ b/tests/DemosHttpTest.php
@@ -8,6 +8,8 @@
 use GuzzleHttp\Client;
 use GuzzleHttp\Exception\ConnectException;
 use GuzzleHttp\Psr7\LazyOpenStream;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\Group;
 use Symfony\Component\Process\Process;
 
 /**
@@ -15,6 +17,7 @@
  *
  * @group demos_http
  */
+#[Group('demos_http')]
 class DemosHttpTest extends DemosTest
 {
     /** @var Process|null */
@@ -158,6 +161,7 @@ public static function provideDemoCallbackErrorCases(): iterable
     /**
      * @dataProvider provideDemoLateOutputErrorCases
      */
+    #[DataProvider('provideDemoLateOutputErrorCases')]
     public function testDemoLateOutputError(string $urlTrigger, string $expectedOutput): void
     {
         $path = '_unit-test/late-output-error.php?' . Callback::URL_QUERY_TRIGGER_PREFIX . $urlTrigger . '=ajax&'
diff --git a/tests/DemosTest.php b/tests/DemosTest.php
index 6e62b71e55..afdb282cbf 100644
--- a/tests/DemosTest.php
+++ b/tests/DemosTest.php
@@ -17,6 +17,7 @@
 use GuzzleHttp\Exception\ServerException;
 use GuzzleHttp\Promise\FulfilledPromise;
 use GuzzleHttp\Psr7\Request;
+use PHPUnit\Framework\Attributes\DataProvider;
 use Psr\Http\Message\RequestInterface;
 use Psr\Http\Message\ResponseInterface;
 
@@ -290,6 +291,7 @@ public static function provideDemosStatusAndHtmlResponseCases(): iterable
     /**
      * @dataProvider provideDemosStatusAndHtmlResponseCases
      */
+    #[DataProvider('provideDemosStatusAndHtmlResponseCases')]
     public function testDemosStatusAndHtmlResponse(string $path): void
     {
         $response = $this->getResponseFromRequest($path);
@@ -322,6 +324,7 @@ public static function provideDemoGetCases(): iterable
     /**
      * @dataProvider provideDemoGetCases
      */
+    #[DataProvider('provideDemoGetCases')]
     public function testDemoGet(string $path): void
     {
         $response = $this->getResponseFromRequest($path);
@@ -398,6 +401,7 @@ public static function provideDemoJsonResponseCases(): iterable
      *
      * @dataProvider provideDemoJsonResponseCases
      */
+    #[DataProvider('provideDemoJsonResponseCases')]
     public function testDemoJsonResponse(string $path, ?string $expectedExceptionMessage = null): void
     {
         if (static::class === self::class) {
@@ -436,6 +440,7 @@ public static function provideDemoSseResponseCases(): iterable
      *
      * @dataProvider provideDemoSseResponseCases
      */
+    #[DataProvider('provideDemoSseResponseCases')]
     public function testDemoSseResponse(string $path): void
     {
         // this test requires SessionTrait, more precisely session_start() which we do not support in non-HTTP testing
@@ -476,6 +481,7 @@ public static function provideDemoJsonResponsePostCases(): iterable
     /**
      * @dataProvider provideDemoJsonResponsePostCases
      */
+    #[DataProvider('provideDemoJsonResponsePostCases')]
     public function testDemoJsonResponsePost(string $path, array $postData): void
     {
         $response = $this->getResponseFromRequest($path, ['form_params' => $postData]);
@@ -488,6 +494,7 @@ public function testDemoJsonResponsePost(string $path, array $postData): void
      *
      * @slowThreshold 1500
      */
+    #[DataProvider('provideDemoCallbackErrorCases')]
     public function testDemoCallbackError(string $path, string $expectedExceptionMessage, array $options = []): void
     {
         if (static::class === self::class) {
diff --git a/tests/ListerTest.php b/tests/ListerTest.php
index 554bcbb916..6d91156e9f 100644
--- a/tests/ListerTest.php
+++ b/tests/ListerTest.php
@@ -9,6 +9,7 @@
 use Atk4\Ui\HtmlTemplate;
 use Atk4\Ui\Lister;
 use Atk4\Ui\View;
+use PHPUnit\Framework\Attributes\DoesNotPerformAssertions;
 
 class ListerTest extends TestCase
 {
@@ -17,6 +18,7 @@ class ListerTest extends TestCase
     /**
      * @doesNotPerformAssertions
      */
+    #[DoesNotPerformAssertions]
     public function testListerRender(): void
     {
         $view = new View();
diff --git a/tests/PaginatorTest.php b/tests/PaginatorTest.php
index 7ddb27369c..b596fc0e19 100644
--- a/tests/PaginatorTest.php
+++ b/tests/PaginatorTest.php
@@ -6,6 +6,7 @@
 
 use Atk4\Core\Phpunit\TestCase;
 use Atk4\Ui\Paginator;
+use PHPUnit\Framework\Attributes\DataProvider;
 
 class PaginatorTest extends TestCase
 {
@@ -34,6 +35,7 @@ public static function providePaginatorCases(): iterable
     /**
      * @dataProvider providePaginatorCases
      */
+    #[DataProvider('providePaginatorCases')]
     public function testPaginator(int $page, int $range, int $total, array $expected): void
     {
         $paginator = new Paginator(['page' => $page, 'range' => $range, 'total' => $total]);
diff --git a/tests/PersistenceUiTest.php b/tests/PersistenceUiTest.php
index 76a25f951d..8f4c10baab 100644
--- a/tests/PersistenceUiTest.php
+++ b/tests/PersistenceUiTest.php
@@ -7,6 +7,7 @@
 use Atk4\Core\Phpunit\TestCase;
 use Atk4\Data\Field;
 use Atk4\Ui\Persistence\Ui as UiPersistence;
+use PHPUnit\Framework\Attributes\DataProvider;
 
 class PersistenceUiTest extends TestCase
 {
@@ -16,6 +17,8 @@ class PersistenceUiTest extends TestCase
      * @dataProvider provideTypecastBidirectionalCases
      * @dataProvider provideTypecastLoadOnlyCases
      */
+    #[DataProvider('provideTypecastBidirectionalCases')]
+    #[DataProvider('provideTypecastLoadOnlyCases')]
     public function testTypecast(array $persistenceSeed, array $fieldSeed, $phpValue, ?string $uiValue, bool $isUiValueNormalized = true): void
     {
         $p = (new UiPersistence())->setDefaults($persistenceSeed);
@@ -203,6 +206,7 @@ public static function provideTypecastLoadOnlyCases(): iterable
      *
      * @dataProvider provideAttributeTypecastCases
      */
+    #[DataProvider('provideAttributeTypecastCases')]
     public function testAttributeTypecast(array $fieldSeed, $phpValue, ?string $uiValue): void
     {
         $p = new UiPersistence();
diff --git a/tests/SessionTraitTest.php b/tests/SessionTraitTest.php
index 0c3cc5aa78..688f7ebd25 100644
--- a/tests/SessionTraitTest.php
+++ b/tests/SessionTraitTest.php
@@ -10,12 +10,16 @@
 use Atk4\Ui\App;
 use Atk4\Ui\Exception;
 use Atk4\Ui\SessionTrait;
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
 
 /**
  * @group require_session
  *
  * @runTestsInSeparateProcesses
  */
+#[Group('require_session')]
+#[RunTestsInSeparateProcesses]
 class SessionTraitTest extends TestCase
 {
     use CreateAppTrait;
diff --git a/tests/TableTest.php b/tests/TableTest.php
index b10c0eb0db..c999061fce 100644
--- a/tests/TableTest.php
+++ b/tests/TableTest.php
@@ -7,6 +7,7 @@
 use Atk4\Core\Phpunit\TestCase;
 use Atk4\Ui\Exception;
 use Atk4\Ui\Table;
+use PHPUnit\Framework\Attributes\DoesNotPerformAssertions;
 
 class TableTest extends TestCase
 {
@@ -15,6 +16,7 @@ class TableTest extends TestCase
     /**
      * @doesNotPerformAssertions
      */
+    #[DoesNotPerformAssertions]
     public function testAddColumnWithoutModel(): void
     {
         $table = new Table();
diff --git a/tests/ViewTest.php b/tests/ViewTest.php
index a28b0e3e3d..5fc62b7476 100644
--- a/tests/ViewTest.php
+++ b/tests/ViewTest.php
@@ -18,6 +18,7 @@
 use Atk4\Ui\Popup;
 use Atk4\Ui\View;
 use Atk4\Ui\VirtualPage;
+use PHPUnit\Framework\Attributes\DataProvider;
 
 class ViewTest extends TestCase
 {
@@ -146,6 +147,7 @@ public function testSetException(): void
      *
      * @dataProvider provideSetNotClosureErrorCases
      */
+    #[DataProvider('provideSetNotClosureErrorCases')]
     public function testSetNotClosureError(string $class): void
     {
         $v = new $class();