diff --git a/.github/workflows/code_checks.yml b/.github/workflows/code_checks.yml
index 3079004..b6e51f1 100644
--- a/.github/workflows/code_checks.yml
+++ b/.github/workflows/code_checks.yml
@@ -32,4 +32,4 @@ jobs:
       - name: Static analysis for tests
         run: ./vendor/bin/phpstan analyse -l max test
       - name: Code Style
-        run: ./vendor/bin/php-cs-fixer fix --dry-run --verbose --config .php_cs.dist ./src ./test
\ No newline at end of file
+        run: ./vendor/bin/php-cs-fixer fix --dry-run --verbose --config .php-cs-fixer.dist.php ./src ./test
\ No newline at end of file
diff --git a/.php_cs.dist b/.php-cs-fixer.dist.php
similarity index 93%
rename from .php_cs.dist
rename to .php-cs-fixer.dist.php
index 0095783..6ca871f 100644
--- a/.php_cs.dist
+++ b/.php-cs-fixer.dist.php
@@ -1,5 +1,5 @@
 <?php
-return PhpCsFixer\Config::create()
+return (new PhpCsFixer\Config())
     ->setRules([
         '@PSR2' => true,
         'array_syntax' => ['syntax' => 'short'],
diff --git a/composer.json b/composer.json
index c917890..73dd4ac 100644
--- a/composer.json
+++ b/composer.json
@@ -2,14 +2,14 @@
     "name" : "genkgo/push",
     "description": "Send push messages to Android and Apple using one interface.",
     "require" : {
-        "php" : "^7.2",
+        "php" : "^7.3",
         "ext-json" : "*",
         "apple/apn-push": "^3.0",
-        "guzzlehttp/guzzle": "^6.0",
+        "guzzlehttp/guzzle": "^7.0",
         "lcobucci/jwt": "^3.3.1"
     },
     "require-dev" : {
-        "phpunit/phpunit": "^8",
+        "phpunit/phpunit": "^9",
         "phpstan/phpstan": "^0.12",
         "phpstan/phpstan-phpunit": "^0.12",
         "friendsofphp/php-cs-fixer": "^2.9"
@@ -26,11 +26,11 @@
     },
     "scripts": {
         "lint": [
-            "./vendor/bin/php-cs-fixer fix --verbose --config .php_cs.dist ./src ./test"
+            "./vendor/bin/php-cs-fixer fix --verbose --config .php-cs-fixer.dist.php ./src ./test"
         ],
         "test": [
             "./vendor/bin/phpunit -c phpunit.xml",
-            "./vendor/bin/php-cs-fixer fix --verbose --dry-run --config .php_cs.dist ./src ./test",
+            "./vendor/bin/php-cs-fixer fix --verbose --dry-run --config .php-cs-fixer.dist.php ./src ./test",
             "./vendor/bin/phpstan analyse -l max src",
             "./vendor/bin/phpstan analyse -l max -c .phpstan.test.neon test"
         ]
diff --git a/phpunit.xml b/phpunit.xml
index e31a6c6..000d85f 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,18 +1,17 @@
 <?xml version="1.0"?>
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
          colors="true"
          verbose="true"
          beStrictAboutOutputDuringTests="true"
-         beStrictAboutTestsThatDoNotTestAnything="true"
->
-    <testsuite name="GenkgoMail tests">
-        <directory>./test/Unit</directory>
-        <directory>./test/Integration</directory>
-    </testsuite>
-    <filter>
-        <whitelist>
-            <directory suffix=".php">./src</directory>
-        </whitelist>
-    </filter>
-</phpunit>
\ No newline at end of file
+         beStrictAboutTestsThatDoNotTestAnything="true">
+  <coverage>
+    <include>
+      <directory suffix=".php">./src</directory>
+    </include>
+  </coverage>
+  <testsuite name="GenkgoMail tests">
+    <directory>./test/Unit</directory>
+    <directory>./test/Integration</directory>
+  </testsuite>
+</phpunit>
diff --git a/test/Integration/CloudMessagingTest.php b/test/Integration/CloudMessagingTest.php
index 74e86ea..09d2adf 100644
--- a/test/Integration/CloudMessagingTest.php
+++ b/test/Integration/CloudMessagingTest.php
@@ -19,13 +19,11 @@ public function testDataIsString(): void
     {
         $provider = $this->createMock(AuthorizationHeaderProviderInterface::class);
         $provider
-            ->expects($this->at(0))
             ->method('__invoke')
             ->willReturn('Bearer test');
 
         $client = $this->createMock(ClientInterface::class);
         $client
-            ->expects($this->at(0))
             ->method('send')
             ->with(
                 $this->callback(
@@ -59,13 +57,11 @@ public function testForbidden(): void
 
         $provider = $this->createMock(AuthorizationHeaderProviderInterface::class);
         $provider
-            ->expects($this->at(0))
             ->method('__invoke')
             ->willReturn('Bearer test');
 
         $client = $this->createMock(ClientInterface::class);
         $client
-            ->expects($this->at(0))
             ->method('send')
             ->willReturnCallback(
                 function (Request $request) {
diff --git a/test/Unit/GatewayTest.php b/test/Unit/GatewayTest.php
index 8ddf3e3..18b417b 100644
--- a/test/Unit/GatewayTest.php
+++ b/test/Unit/GatewayTest.php
@@ -19,11 +19,13 @@ public function testSend(): void
         $recipient = new AndroidDeviceRecipient('token');
 
         $sender = $this->createMock(SenderInterface::class);
-        $sender->expects($this->at(0))->method('supports')->with($message, $recipient)->willReturn(true);
-        $sender->expects($this->at(1))->method('send')->with($message, $recipient);
+        $sender->method('supports')->with($message, $recipient)->willReturn(true);
+        $sender->method('send')->with($message, $recipient);
 
         $gateway = new Gateway([$sender]);
         $gateway->send($message, $recipient);
+
+        $this->addToAssertionCount(1);
     }
 
     public function testExceptionUnsupportedSender(): void
@@ -34,7 +36,7 @@ public function testExceptionUnsupportedSender(): void
         $recipient = new AndroidDeviceRecipient('token');
 
         $sender = $this->createMock(SenderInterface::class);
-        $sender->expects($this->at(0))->method('supports')->with($message, $recipient)->willReturn(false);
+        $sender->method('supports')->with($message, $recipient)->willReturn(false);
 
         $gateway = new Gateway([$sender]);
         $gateway->send($message, $recipient);