diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index e5d071b..62c6a59 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -24,6 +24,7 @@ jobs:
           - '7.1'
           - '7.0'
         phpunit-version:
+          - '12.1.0'
           - '12.0.0'
           - '11.5.0'
           - '11.4.0'
@@ -156,6 +157,8 @@ jobs:
             phpunit-version: '6.0.0'
 
           # PHP 8.2 Exclusions
+          - php-version: '8.2'
+            phpunit-version: '12.1.0'
           - php-version: '8.2'
             phpunit-version: '12.0.0'
           - php-version: '8.2'
@@ -204,6 +207,8 @@ jobs:
             phpunit-version: '6.0.0'
 
           # PHP 8.1 Exclusions
+          - php-version: '8.1'
+            phpunit-version: '12.1.0'
           - php-version: '8.1'
             phpunit-version: '12.0.0'
           - php-version: '8.1'
@@ -264,6 +269,8 @@ jobs:
             phpunit-version: '6.0.0'
 
           # PHP 8.0 Exclusions
+          - php-version: '8.0'
+            phpunit-version: '12.1.0'
           - php-version: '8.0'
             phpunit-version: '12.0.0'
           - php-version: '8.0'
@@ -332,6 +339,8 @@ jobs:
             phpunit-version: '6.0.0'
             
           # PHP 7.4 Exclusions
+          - php-version: '7.4'
+            phpunit-version: '12.1.0'
           - php-version: '7.4'
             phpunit-version: '12.0.0'
           - php-version: '7.4'
@@ -386,6 +395,8 @@ jobs:
             phpunit-version: '6.0.0'
 
           # PHP 7.3 Exclusions
+          - php-version: '7.3'
+            phpunit-version: '12.1.0'
           - php-version: '7.3'
             phpunit-version: '12.0.0'
           - php-version: '7.3'
@@ -414,6 +425,8 @@ jobs:
             phpunit-version: '10.0.0'
           
           # PHP 7.2 Exclusions
+          - php-version: '7.2'
+            phpunit-version: '12.1.0'
           - php-version: '7.2'
             phpunit-version: '12.0.0'
           - php-version: '7.2'
@@ -456,6 +469,8 @@ jobs:
             phpunit-version: '9.0.0'
           
           # PHP 7.1 Exclusions
+          - php-version: '7.1'
+            phpunit-version: '12.1.0'
           - php-version: '7.1'
             phpunit-version: '12.0.0'
           - php-version: '7.1'
@@ -510,6 +525,8 @@ jobs:
             phpunit-version: '8.0.0'
       
           # PHP 7.0 Exclusions
+          - php-version: '7.0'
+            phpunit-version: '12.1.0'
           - php-version: '7.0'
             phpunit-version: '12.0.0'
           - php-version: '7.0'
diff --git a/autoload.php b/autoload.php
index f567a6a..e16fa67 100644
--- a/autoload.php
+++ b/autoload.php
@@ -29,10 +29,17 @@ class_alias(
 }
 
 if (! class_exists(\PHPUnit\Framework\MockObject\Builder\InvocationMocker::class)) {
-    class_alias(
-        \PHPUnit_Framework_MockObject_Builder_InvocationMocker::class,
-        \PHPUnit\Framework\MockObject\Builder\InvocationMocker::class
-    );
+    if (class_exists(\PHPUnit\Framework\MockObject\InvocationStubberImplementation::class)) {
+        class_alias(
+            \PHPUnit\Framework\MockObject\InvocationStubberImplementation::class,
+            \PHPUnit\Framework\MockObject\Builder\InvocationMocker::class
+        );
+    } else {
+        class_alias(
+            \PHPUnit_Framework_MockObject_Builder_InvocationMocker::class,
+            \PHPUnit\Framework\MockObject\Builder\InvocationMocker::class
+        );
+    }
 }
 
 if (class_exists(\PHPUnit\Framework\MockObject\Rule\MethodName::class)) {
diff --git a/classes/MockObjectProxyReturnTypes120.php b/classes/MockObjectProxyReturnTypes120.php
index f30503e..8cb79b8 100644
--- a/classes/MockObjectProxyReturnTypes120.php
+++ b/classes/MockObjectProxyReturnTypes120.php
@@ -4,8 +4,8 @@
 
 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\InvocationStubberImplementation as BuilderInvocationMocker;
+use PHPUnit\Framework\MockObject\InvocationStubber;
 use PHPUnit\Framework\MockObject\InvocationHandler;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\MockObject\Rule\InvocationOrder;
diff --git a/composer.json b/composer.json
index 702ebe8..bbd0703 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,7 @@
     },
     "require": {
         "php": ">=7",
-        "phpunit/phpunit": "^6 || ^7 || ^8 || ^9 || ^10.0.17 || ^11 || ^12",
+        "phpunit/phpunit": "^6 || ^7 || ^8 || ^9 || ^10.0.17 || ^11 || ^12.0.9",
         "php-mock/php-mock-integration": "^3.0"
     },
     "require-dev": {