diff --git a/src/Stub.php b/src/Stub.php
index ae31b40..d3a3fcc 100644
--- a/src/Stub.php
+++ b/src/Stub.php
@@ -9,7 +9,8 @@
 use Codeception\Stub\StubMarshaler;
 use Exception;
 use LogicException;
-use PHPUnit\Framework\MockObject\Generator;
+use PHPUnit\Framework\MockObject\Generator as LegacyGenerator;
+use PHPUnit\Framework\MockObject\Generator\Generator;
 use PHPUnit\Framework\MockObject\MockObject as PHPUnitMockObject;
 use PHPUnit\Framework\MockObject\Rule\AnyInvokedCount;
 use PHPUnit\Framework\MockObject\Stub\ConsecutiveCalls;
@@ -433,7 +434,12 @@ private static function doGenerateMock($args, $isAbstract = false)
     {
         $testCase = self::extractTestCaseFromArgs($args);
         $methodName = $isAbstract ? 'getMockForAbstractClass' : 'getMock';
-        $generatorClass = new Generator;
+        // PHPUnit 10.3 changed the namespace
+        if (version_compare(PHPUnitVersion::series(), '10.3', '>=')) {
+            $generatorClass = new Generator();
+        } else {
+            $generatorClass = new LegacyGenerator();
+        }
 
         // using PHPUnit 5.4 mocks registration
         if (version_compare(PHPUnitVersion::series(), '5.4', '>=')
diff --git a/tests/StubTest.php b/tests/StubTest.php
index 9325ad4..e56c3b3 100644
--- a/tests/StubTest.php
+++ b/tests/StubTest.php
@@ -387,12 +387,6 @@ public function testStubMakeEmptyInterface()
         $stub = Stub::makeEmpty(Countable::class, ['count' => 5]);
         $this->assertEquals(5, $stub->count());
     }
-
-    private function assertObjectHasProperty(string $propertyName, object $object): void
-    {
-        $hasProperty = (new ReflectionObject($object))->hasProperty($propertyName);
-        $this->assertTrue($hasProperty, sprintf("Object has no attribute %s", $propertyName));
-    }
 }
 
 class MyClassWithPrivateProperties