diff --git a/phpunit.xml b/phpunit.xml
index cfc43d2046..353abc4eec 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -4,8 +4,7 @@
          processIsolation="false"
          stopOnFailure="false"
          bootstrap="tests/bootstrap.php"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/11.5/phpunit.xsd"
->
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.5/phpunit.xsd">
   <testsuites>
       <testsuite name="Features">
         <directory>tests/Feature</directory>
diff --git a/tests/Feature/Api/PerformanceApiTest.php b/tests/Feature/Api/PerformanceApiTest.php
index 004177d758..1b96c73ce3 100644
--- a/tests/Feature/Api/PerformanceApiTest.php
+++ b/tests/Feature/Api/PerformanceApiTest.php
@@ -41,7 +41,7 @@ private function calculateUnitTime($times = 100)
     }
 
     // Endpoints to be tested
-    private $endpoints = [
+    private static $endpoints = [
         ['l5-swagger.default.oauth2_callback', []],
         ['passport.tokens.index', []],
         ['passport.clients.index', []],
@@ -77,11 +77,11 @@ private function calculateUnitTime($times = 100)
 
     const DESIRABLE_ROUTE_SPEED = 11;
 
-    public function RoutesListProvider()
+    public static function RoutesListProvider()
     {
         file_exists('coverage') ?: mkdir('coverage');
 
-        return $this->endpoints;
+        return self::$endpoints;
     }
 
     /**
diff --git a/tests/Feature/Api/PerformanceRoutesTest.php b/tests/Feature/Api/PerformanceRoutesTest.php
index 7f3e000ad0..4331a73f06 100644
--- a/tests/Feature/Api/PerformanceRoutesTest.php
+++ b/tests/Feature/Api/PerformanceRoutesTest.php
@@ -40,7 +40,7 @@ private function calculateUnitTime($times = 100)
     }
 
     // Endpoints to be tested
-    private $endpoints = [
+    private static $endpoints = [
         ['groups.index', []],
         ['users.index', []],
         ['auth-clients.index', []],
@@ -79,11 +79,11 @@ private function calculateUnitTime($times = 100)
 
     const DESIRABLE_ROUTE_SPEED = 11;
 
-    public function RoutesListProvider()
+    public static function RoutesListProvider()
     {
         file_exists('coverage') ?: mkdir('coverage');
 
-        return $this->endpoints;
+        return self::endpoints;
     }
 
     /**
diff --git a/tests/Feature/Api/ProcessPatternsTest.php b/tests/Feature/Api/ProcessPatternsTest.php
index d9b8bb7b63..8ae1afb598 100644
--- a/tests/Feature/Api/ProcessPatternsTest.php
+++ b/tests/Feature/Api/ProcessPatternsTest.php
@@ -52,14 +52,14 @@ public function testProcessPatterns($type, $bpmnFile, $context = [])
      *
      * @return array
      */
-    public function prepareTestCasesProvider()
+    public static function prepareTestCasesProvider()
     {
         $tests = [];
-        $tests = $this->prepareTestCases('Conditional_StartEvent.bpmn', $tests);
-        $tests = $this->prepareTestCases('Conditional_IntermediateEvent.bpmn', $tests);
-        $tests = $this->prepareTestCases('MultiInstance_SequentialCallActivity.bpmn', $tests);
-        $tests = $this->prepareTestCases('Loop_Task.bpmn', $tests);
-        $tests = $this->prepareTestCases('SignalWithCustomPayload.bpmn', $tests);
+        $tests = self::prepareTestCases('Conditional_StartEvent.bpmn', $tests);
+        $tests = self::prepareTestCases('Conditional_IntermediateEvent.bpmn', $tests);
+        $tests = self::prepareTestCases('MultiInstance_SequentialCallActivity.bpmn', $tests);
+        $tests = self::prepareTestCases('Loop_Task.bpmn', $tests);
+        $tests = self::prepareTestCases('SignalWithCustomPayload.bpmn', $tests);
 
         return $tests;
     }
@@ -72,7 +72,7 @@ public function prepareTestCasesProvider()
      *
      * @return array
      */
-    private function prepareTestCases($bpmnFile, array $tests)
+    private static function prepareTestCases($bpmnFile, array $tests)
     {
         $file = "{$this->basePath}{$bpmnFile}";
         $name = basename($bpmnFile, '.bpmn');
diff --git a/tests/Feature/ImportExport/Api/ExportImportTest.php b/tests/Feature/ImportExport/Api/ExportImportTest.php
index 6f1178c1c4..2de9c8bd59 100644
--- a/tests/Feature/ImportExport/Api/ExportImportTest.php
+++ b/tests/Feature/ImportExport/Api/ExportImportTest.php
@@ -237,7 +237,7 @@ public function testExportImportFull($importType)
         $this->assertAssetsWasImported($scenario);
     }
 
-    public function importType()
+    public static function importType()
     {
         return [
             ['update'],