diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 29053d3..e5d071b 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -13,6 +13,7 @@ jobs:
     strategy:
       matrix:
         php-version:
+          - '8.4'
           - '8.3'
           - '8.2'
           - '8.1'
@@ -23,6 +24,10 @@ jobs:
           - '7.1'
           - '7.0'
         phpunit-version:
+          - '12.0.0'
+          - '11.5.0'
+          - '11.4.0'
+          - '11.3.0'
           - '11.2.0'
           - '11.1.0'
           - '11.0.0'
@@ -58,6 +63,52 @@ jobs:
           - '6.0.0'
 
         exclude:
+          # PHP 8.4 Exclusions
+          - php-version: '8.4'
+            phpunit-version: '9.4.0'
+          - php-version: '8.4'
+            phpunit-version: '9.3.0'
+          - php-version: '8.4'
+            phpunit-version: '9.2.0'
+          - php-version: '8.4'
+            phpunit-version: '9.1.0'
+          - php-version: '8.4'
+            phpunit-version: '9.0.0'
+          - php-version: '8.4'
+            phpunit-version: '8.4.0'
+          - php-version: '8.4'
+            phpunit-version: '8.3.0'
+          - php-version: '8.4'
+            phpunit-version: '8.2.0'
+          - php-version: '8.4'
+            phpunit-version: '8.1.0'
+          - php-version: '8.4'
+            phpunit-version: '8.0.0'
+          - php-version: '8.4'
+            phpunit-version: '7.5.0'
+          - php-version: '8.4'
+            phpunit-version: '7.4.0'
+          - php-version: '8.4'
+            phpunit-version: '7.3.0'
+          - php-version: '8.4'
+            phpunit-version: '7.2.0'
+          - php-version: '8.4'
+            phpunit-version: '7.1.0'
+          - php-version: '8.4'
+            phpunit-version: '7.0.0'
+          - php-version: '8.4'
+            phpunit-version: '6.5.0'
+          - php-version: '8.4'
+            phpunit-version: '6.4.0'
+          - php-version: '8.4'
+            phpunit-version: '6.3.0'
+          - php-version: '8.4'
+            phpunit-version: '6.2.0'
+          - php-version: '8.4'
+            phpunit-version: '6.1.0'
+          - php-version: '8.4'
+            phpunit-version: '6.0.0'
+        
           # PHP 8.3 Exclusions
           - php-version: '8.3'
             phpunit-version: '9.4.0'
@@ -105,6 +156,8 @@ jobs:
             phpunit-version: '6.0.0'
 
           # PHP 8.2 Exclusions
+          - php-version: '8.2'
+            phpunit-version: '12.0.0'
           - php-version: '8.2'
             phpunit-version: '9.4.0'
           - php-version: '8.2'
@@ -151,6 +204,14 @@ jobs:
             phpunit-version: '6.0.0'
 
           # PHP 8.1 Exclusions
+          - php-version: '8.1'
+            phpunit-version: '12.0.0'
+          - php-version: '8.1'
+            phpunit-version: '11.5.0'
+          - php-version: '8.1'
+            phpunit-version: '11.4.0'
+          - php-version: '8.1'
+            phpunit-version: '11.3.0'
           - php-version: '8.1'
             phpunit-version: '11.2.0'
           - php-version: '8.1'
@@ -203,6 +264,14 @@ jobs:
             phpunit-version: '6.0.0'
 
           # PHP 8.0 Exclusions
+          - php-version: '8.0'
+            phpunit-version: '12.0.0'
+          - php-version: '8.0'
+            phpunit-version: '11.5.0'
+          - php-version: '8.0'
+            phpunit-version: '11.4.0'
+          - php-version: '8.0'
+            phpunit-version: '11.3.0'
           - php-version: '8.0'
             phpunit-version: '11.2.0'
           - php-version: '8.0'
@@ -263,6 +332,14 @@ jobs:
             phpunit-version: '6.0.0'
             
           # PHP 7.4 Exclusions
+          - php-version: '7.4'
+            phpunit-version: '12.0.0'
+          - php-version: '7.4'
+            phpunit-version: '11.5.0'
+          - php-version: '7.4'
+            phpunit-version: '11.4.0'
+          - php-version: '7.4'
+            phpunit-version: '11.3.0'
           - php-version: '7.4'
             phpunit-version: '11.2.0'
           - php-version: '7.4'
@@ -309,6 +386,14 @@ jobs:
             phpunit-version: '6.0.0'
 
           # PHP 7.3 Exclusions
+          - php-version: '7.3'
+            phpunit-version: '12.0.0'
+          - php-version: '7.3'
+            phpunit-version: '11.5.0'
+          - php-version: '7.3'
+            phpunit-version: '11.4.0'
+          - php-version: '7.3'
+            phpunit-version: '11.3.0'
           - php-version: '7.3'
             phpunit-version: '11.2.0'
           - php-version: '7.3'
@@ -329,6 +414,14 @@ jobs:
             phpunit-version: '10.0.0'
           
           # PHP 7.2 Exclusions
+          - php-version: '7.2'
+            phpunit-version: '12.0.0'
+          - php-version: '7.2'
+            phpunit-version: '11.5.0'
+          - php-version: '7.2'
+            phpunit-version: '11.4.0'
+          - php-version: '7.2'
+            phpunit-version: '11.3.0'
           - php-version: '7.2'
             phpunit-version: '11.2.0'
           - php-version: '7.2'
@@ -363,6 +456,14 @@ jobs:
             phpunit-version: '9.0.0'
           
           # PHP 7.1 Exclusions
+          - php-version: '7.1'
+            phpunit-version: '12.0.0'
+          - php-version: '7.1'
+            phpunit-version: '11.5.0'
+          - php-version: '7.1'
+            phpunit-version: '11.4.0'
+          - php-version: '7.1'
+            phpunit-version: '11.3.0'
           - php-version: '7.1'
             phpunit-version: '11.2.0'
           - php-version: '7.1'
@@ -409,6 +510,14 @@ jobs:
             phpunit-version: '8.0.0'
       
           # PHP 7.0 Exclusions
+          - php-version: '7.0'
+            phpunit-version: '12.0.0'
+          - php-version: '7.0'
+            phpunit-version: '11.5.0'
+          - php-version: '7.0'
+            phpunit-version: '11.4.0'
+          - php-version: '7.0'
+            phpunit-version: '11.3.0'
           - php-version: '7.0'
             phpunit-version: '11.2.0'
           - php-version: '7.0'
diff --git a/autoload.php b/autoload.php
index e59f8ca..f567a6a 100644
--- a/autoload.php
+++ b/autoload.php
@@ -90,6 +90,11 @@ class_alias(
 }
 
 if ($hasVersion
+    && version_compare(\PHPUnit\Runner\Version::id(), '12.0.0') >= 0
+) {
+    class_alias(\phpmock\phpunit\DefaultArgumentRemoverReturnTypes120::class, \phpmock\phpunit\DefaultArgumentRemover::class);
+    class_alias(\phpmock\phpunit\MockObjectProxyReturnTypes120::class, \phpmock\phpunit\MockObjectProxy::class);
+} elseif ($hasVersion
     && version_compare(\PHPUnit\Runner\Version::id(), '10.0.0') >= 0
 ) {
     class_alias(\phpmock\phpunit\DefaultArgumentRemoverReturnTypes100::class, \phpmock\phpunit\DefaultArgumentRemover::class);
diff --git a/classes/DefaultArgumentRemoverReturnTypes120.php b/classes/DefaultArgumentRemoverReturnTypes120.php
new file mode 100644
index 0000000..8cce8fa
--- /dev/null
+++ b/classes/DefaultArgumentRemoverReturnTypes120.php
@@ -0,0 +1,128 @@
+<?php
+
+namespace phpmock\phpunit;
+
+use phpmock\generator\MockFunctionGenerator;
+use PHPUnit\Framework\MockObject\Invocation;
+use PHPUnit\Framework\MockObject\Rule\InvocationOrder;
+use ReflectionClass;
+
+/**
+ * Removes default arguments from the invocation.
+ *
+ * @author Markus Malkusch <markus@malkusch.de>
+ * @link bitcoin:1335STSwu9hST4vcMRppEPgENMHD2r1REK Donations
+ * @license http://www.wtfpl.net/txt/copying/ WTFPL
+ * @internal
+ */
+class DefaultArgumentRemoverReturnTypes120 extends InvocationOrder
+{
+    /**
+     * @SuppressWarnings(PHPMD)
+     */
+    public function invokedDo(Invocation $invocation): void
+    {
+    }
+
+    /**
+     * @SuppressWarnings(PHPMD)
+     */
+    public function matches(Invocation $invocation) : bool
+    {
+        $iClass = class_exists(Invocation::class);
+
+        if ($iClass
+            || $invocation instanceof Invocation\StaticInvocation
+        ) {
+            $this->removeDefaultArguments(
+                $invocation,
+                $iClass ? Invocation::class : Invocation\StaticInvocation::class
+            );
+        } elseif (!$this->shouldRemoveDefaultArgumentsWithReflection($invocation)) {
+            MockFunctionGenerator::removeDefaultArguments($invocation->parameters);
+        }
+
+        return false;
+    }
+
+    public function verify() : void
+    {
+    }
+
+    /**
+     * This method is not defined in the interface, but used in
+     * PHPUnit_Framework_MockObject_InvocationMocker::hasMatchers().
+     *
+     * @return boolean
+     * @see \PHPUnit_Framework_MockObject_InvocationMocker::hasMatchers()
+     */
+    public function hasMatchers()
+    {
+        return false;
+    }
+
+    public function toString() : string
+    {
+        return __CLASS__;
+    }
+
+    /**
+     * Remove default arguments from StaticInvocation or its children (hack)
+     *
+     * @SuppressWarnings(PHPMD)
+     */
+    private function removeDefaultArguments(Invocation $invocation, string $class)
+    {
+        if ($this->shouldRemoveDefaultArgumentsWithReflection($invocation)) {
+            return;
+        }
+
+        $remover = function () {
+            MockFunctionGenerator::removeDefaultArguments($this->parameters);
+        };
+
+        $remover->bindTo($invocation, $class)();
+    }
+
+    /**
+     * Alternative to remove default arguments from StaticInvocation or its children (hack)
+     *
+     * @SuppressWarnings(PHPMD.StaticAccess)
+     */
+    public static function removeDefaultArgumentsWithReflection(Invocation $invocation): Invocation
+    {
+        if (!(new self())->shouldRemoveDefaultArgumentsWithReflection($invocation)) {
+            return $invocation;
+        }
+
+        $reflection = new ReflectionClass($invocation);
+
+        $reflectionReturnType = $reflection->getProperty('returnType');
+        $reflectionReturnType->setAccessible(true);
+
+        $reflectionIsOptional = $reflection->getProperty('isReturnTypeNullable');
+        $reflectionIsOptional->setAccessible(true);
+
+        $returnType = $reflectionReturnType->getValue($invocation);
+
+        if ($reflectionIsOptional->getValue($invocation)) {
+            $returnType = '?' . $returnType;
+        }
+
+        $parameters = $invocation->parameters();
+        MockFunctionGenerator::removeDefaultArguments($parameters);
+
+        return new Invocation(
+            $invocation->className(),
+            $invocation->methodName(),
+            $parameters,
+            $returnType,
+            $invocation->object()
+        );
+    }
+
+    protected function shouldRemoveDefaultArgumentsWithReflection(Invocation $invocation)
+    {
+        return method_exists($invocation, 'parameters');
+    }
+}
diff --git a/classes/MockObjectProxyReturnTypes120.php b/classes/MockObjectProxyReturnTypes120.php
new file mode 100644
index 0000000..f30503e
--- /dev/null
+++ b/classes/MockObjectProxyReturnTypes120.php
@@ -0,0 +1,100 @@
+<?php
+
+namespace phpmock\phpunit;
+
+use phpmock\integration\MockDelegateFunctionBuilder;
+use PHPUnit\Framework\Constraint\Constraint;
+use PHPUnit\Framework\MockObject\Builder\InvocationMocker as BuilderInvocationMocker;
+use PHPUnit\Framework\MockObject\Builder\InvocationStubber;
+use PHPUnit\Framework\MockObject\InvocationHandler;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\MockObject\Rule\InvocationOrder;
+use PHPUnit\Framework\MockObject\Runtime\PropertyHook;
+
+/**
+ * Proxy for PHPUnit's PHPUnit_Framework_MockObject_MockObject.
+ *
+ * @author Markus Malkusch <markus@malkusch.de>
+ * @link bitcoin:1335STSwu9hST4vcMRppEPgENMHD2r1REK Donations
+ * @license http://www.wtfpl.net/txt/copying/ WTFPL
+ * @internal
+ */
+class MockObjectProxyReturnTypes120 implements MockObject
+{
+    /**
+     * @var MockObject $mockObject The mock object.
+     */
+    private $mockObject;
+
+    /**
+     * Inject the subject.
+     *
+     * @param MockObject $mockObject   The subject.
+     */
+    public function __construct(MockObject $mockObject)
+    {
+        $this->mockObject = $mockObject;
+    }
+
+    /**
+     * @SuppressWarnings(PHPMD)
+     */
+    // @codingStandardsIgnoreStart
+    public function __phpunit_getInvocationHandler(): InvocationHandler
+    {
+        return $this->mockObject->__phpunit_getInvocationHandler();
+    }
+
+    /**
+     * @SuppressWarnings(PHPMD)
+     */
+    // @codingStandardsIgnoreStart
+    public function __phpunit_setOriginalObject(object $originalObject) : void
+    {
+        // @codingStandardsIgnoreEnd
+        $this->mockObject->__phpunit_setOriginalObject($originalObject);
+    }
+
+    /**
+     * @SuppressWarnings(PHPMD)
+     */
+    // @codingStandardsIgnoreStart
+    public function __phpunit_verify(bool $unsetInvocationMocker = true) : void
+    {
+        // @codingStandardsIgnoreEnd
+        $this->mockObject->__phpunit_verify($unsetInvocationMocker);
+    }
+
+    public function expects(InvocationOrder $matcher) : BuilderInvocationMocker
+    {
+        return $this->mockObject->expects($matcher)->method(MockDelegateFunctionBuilder::METHOD);
+    }
+
+    public function method(Constraint|PropertyHook|string $constraint): InvocationStubber
+    {
+        return $this->mockObject->method($constraint);
+    }
+
+    /**
+     * This method is not part of the contract but was found in
+     * PHPUnit's mocked_class.tpl.dist.
+     *
+     * @SuppressWarnings(PHPMD)
+     */
+    // @codingStandardsIgnoreStart
+    public function __phpunit_hasMatchers() : bool
+    {
+        // @codingStandardsIgnoreEnd
+        return $this->mockObject->__phpunit_hasMatchers();
+    }
+
+    /**
+     * @SuppressWarnings(PHPMD)
+     */
+    // @codingStandardsIgnoreStart
+    public function __phpunit_setReturnValueGeneration(bool $returnValueGeneration) : void
+    {
+        // @codingStandardsIgnoreEnd
+        $this->mockObject->__phpunit_setReturnValueGeneration($returnValueGeneration);
+    }
+}
diff --git a/classes/PHPMock.php b/classes/PHPMock.php
index 543db17..4575504 100644
--- a/classes/PHPMock.php
+++ b/classes/PHPMock.php
@@ -66,10 +66,12 @@ public function getFunctionMock($namespace, $name)
         $delegateBuilder->build($name);
 
         $builder = $this->getMockBuilder($delegateBuilder->getFullyQualifiedClassName());
-        if (is_callable([$builder, 'addMethods'])) {
-            $builder->addMethods([$name]);
+        if (is_callable([$builder, 'onlyMethods'])) {
+            $builder->onlyMethods([MockDelegateFunctionBuilder::METHOD, $name]);
+        } elseif (is_callable([$builder, 'setMethods'])) {
+            $builder->setMethods([MockDelegateFunctionBuilder::METHOD, $name]);
         }
-        $mock = $builder->getMockForAbstractClass();
+        $mock = $builder->getMock();
         $this->addMatcher($mock, $name);
 
         $functionMockBuilder = new MockBuilder();
@@ -199,8 +201,9 @@ private function prepareCustomTemplates()
         }
 
         $mockMethodClasses = [
-            'PHPUnit\\Framework\\MockObject\\Generator\\MockMethod',
-            'PHPUnit\\Framework\\MockObject\\MockMethod',
+            'PHPUnit\\Framework\\MockObject\\Generator\\DoubledMethod', // PHPUnit 12
+            'PHPUnit\\Framework\\MockObject\\Generator\\MockMethod',    // PHPUnit 10-11
+            'PHPUnit\\Framework\\MockObject\\MockMethod',               // PHPUnit 9
         ];
 
         foreach ($mockMethodClasses as $mockMethodClass) {
diff --git a/composer.json b/composer.json
index 9218934..702ebe8 100644
--- a/composer.json
+++ b/composer.json
@@ -19,8 +19,8 @@
     },
     "require": {
         "php": ">=7",
-        "phpunit/phpunit": "^6 || ^7 || ^8 || ^9 || ^10.0.17 || ^11",
-        "php-mock/php-mock-integration": "^2.3"
+        "phpunit/phpunit": "^6 || ^7 || ^8 || ^9 || ^10.0.17 || ^11 || ^12",
+        "php-mock/php-mock-integration": "^3.0"
     },
     "require-dev": {
         "mockery/mockery": "^1.3.6"
diff --git a/tests/MockObjectProxyTest.php b/tests/MockObjectProxyTest.php
index 482e052..e9f35e4 100644
--- a/tests/MockObjectProxyTest.php
+++ b/tests/MockObjectProxyTest.php
@@ -4,6 +4,7 @@
 
 use Mockery;
 use phpmock\integration\MockDelegateFunctionBuilder;
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\MockObject\Builder\InvocationMocker;
 use PHPUnit\Framework\MockObject\ConfigurableMethod;
 use PHPUnit\Framework\MockObject\InvocationHandler;
@@ -137,6 +138,7 @@ public function testHasMatcher()
      * @test
      * @dataProvider provideTestProxiedMethods
      */
+    #[DataProvider('provideTestProxiedMethods')]
     public function testProxiedMethods($method, array $arguments = [], $expected = null)
     {
         $mock = Mockery::mock(MockObject::class);