diff --git a/composer.json b/composer.json
index f5dc095..a1c2c90 100644
--- a/composer.json
+++ b/composer.json
@@ -1,43 +1,43 @@
 {
   "name": "keruald/mailgun",
   "description": "Mailgun API client to retrieve a mail",
   "license": "BSD-2-Clause",
   "authors": [
     {
       "name": "Sébastien Santoro",
       "email": "dereckson@espace-win.org"
     },
     {
       "name": "Yassine Hadj Messaoud",
       "email": "modepadu95@riseup.net"
     }
   ],
   "keywords": [
     "keruald",
     "Mailgun"
   ],
   "support": {
     "irc": "irc://irc.freenode.net/wolfplex",
     "issues": "https://devcentral.nasqueron.org"
   },
   "require": {
-    "php": ">=5.6.0",
-    "guzzlehttp/psr7": "~1.3",
-    "guzzlehttp/guzzle": "~6.0"
+    "php": ">=7.3",
+    "guzzlehttp/psr7": "^2.4.1",
+    "guzzlehttp/guzzle": "^7.5.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "5.0.*",
-    "psy/psysh": "dev-master",
-    "squizlabs/php_codesniffer": "*",
-    "mockery/mockery": "^0.9.5"
+    "phpunit/phpunit": "^9.5.24",
+    "psy/psysh": "dev-main",
+    "squizlabs/php_codesniffer": "^3.7.1",
+    "mockery/mockery": "^1.5.1"
   },
   "autoload": {
     "psr-4": {
       "Keruald\\Mailgun\\": "src/",
       "Keruald\\Mailgun\\Tests\\": "tests/"
     }
   },
   "scripts": {
     "test": "phpunit tests"
   }
 }
diff --git a/phpunit.xml b/phpunit.xml
index 2124462..1a00af0 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,13 +1,16 @@
-<?xml version="1.0" encoding="utf-8" ?>
-<phpunit bootstrap="./vendor/autoload.php">
-    <testsuites>
-        <testsuite name="Library test suite">
-            <directory>./tests/</directory>
-        </testsuite>
-    </testsuites>
-    <filter>
-        <whitelist>
-            <directory suffix=".php">src/</directory>
-        </whitelist>
-    </filter>
+<?xml version="1.0" encoding="utf-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         bootstrap="./vendor/autoload.php"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+         colors="true">
+  <coverage>
+    <include>
+      <directory suffix=".php">src/</directory>
+    </include>
+  </coverage>
+  <testsuites>
+    <testsuite name="Library test suite">
+      <directory>./tests/</directory>
+    </testsuite>
+  </testsuites>
 </phpunit>
diff --git a/tests/MailgunMessageFactoryTest.php b/tests/MailgunMessageFactoryTest.php
index 5da4e70..c5406da 100644
--- a/tests/MailgunMessageFactoryTest.php
+++ b/tests/MailgunMessageFactoryTest.php
@@ -1,55 +1,53 @@
 <?php
 
 namespace Keruald\Mailgun\Tests;
 
 use Keruald\Mailgun\MailgunMessageFactory;
 use Keruald\Mailgun\MailgunMessage;
 
-use PHPUnit_Framework_TestCase as TestCase;
+use PHPUnit\Framework\TestCase;
 
 use stdClass;
 
 class MailgunMessageFactoryTest extends TestCase {
 
     use WithMockHttpClient;
 
     /**
      * @var \Keruald\Mailgun\MailgunMessageFactory
      */
     private $factory;
 
-    public function setUp () {
+    public function setUp () : void {
         $client = self::mockHttpClient();
         $this->factory = new MailgunMessageFactory($client, "0000");
     }
 
     public function testGetMessage () {
         $message = $this->factory->getMessage("http://api/somemessage");
         $this->assertInstanceOf(MailgunMessage::class, $message);
     }
 
     public function testGetMessageFromPayload () {
         $payload = self::mockEventPayload();
         $message = $this->factory->getMessageFromPayload($payload);
         $this->assertInstanceOf(MailgunMessage::class, $message);
     }
 
-    /**
-     * @expectedException \InvalidArgumentException
-     */
     public function testGetMessageFromPayloadThrowsExceptionWhenPayloadDoesNotContainUrlInformation () {
+        $this->expectException(\InvalidArgumentException::class);
         $this->factory->getMessageFromPayload(new stdClass);
     }
 
     public function testFetchMessage () {
         $message = $this->factory->fetchMessage("http://api/somemessage");
         $this->assertInstanceOf("stdClass", $message);
     }
 
     public function testFetchMessageFromPayload () {
         $payload = self::mockEventPayload();
         $message = $this->factory->fetchMessageFromPayload($payload);
         $this->assertInstanceOf("stdClass", $message);
     }
 
 }
diff --git a/tests/MailgunMessageTest.php b/tests/MailgunMessageTest.php
index 04001df..b2f29c9 100644
--- a/tests/MailgunMessageTest.php
+++ b/tests/MailgunMessageTest.php
@@ -1,68 +1,64 @@
 <?php
 
 namespace Keruald\Mailgun\Tests;
 
 use Keruald\Mailgun\MailgunMessage;
 
-use PHPUnit_Framework_TestCase as TestCase;
+use PHPUnit\Framework\TestCase;
 use stdClass;
 
 class MailgunMessageTest extends TestCase {
 
     use WithMockHttpClient;
 
     /**
      * @var MailgunMessage
      */
     private $message;
 
-    public function setUp() {
+    public function setUp() : void {
         $client = self::mockHttpClient();
         $this->message = new MailgunMessage($client, "https://api/msg", "0000");
     }
 
     public function testGet () {
         $this->assertEquals(
             json_decode(self::mockHttpClientResponseBody()),
             $this->message->get()
         );
     }
 
     public function testGetWhenMessageIsAlreadyCached () {
         $this->message->get();
         $this->assertEquals(
             json_decode(self::mockHttpClientResponseBody()),
             $this->message->get()
         );
     }
 
-    /**
-     * @expectedException \RuntimeException
-     */
     public function testFetchThrowsExceptionWhenStatusCodeIsNot200 () {
+        $this->expectException(\RuntimeException::class);
         $client = self::mockHttpClientWithCustomResponse(500, null);
         $message = new MailgunMessage($client, "https://api/msg", "0000");
         $message->get();
     }
 
     public function testLoadFromEventPayload () {
         $client = self::mockHttpClient();
         $payload = self::mockEventPayload();
         $message = MailgunMessage::loadFromEventPayload($client, $payload, "0000");
         $this->assertEquals(
             json_decode(self::mockHttpClientResponseBody()),
             $message->get()
         );
     }
 
-    /**
-     * @expectedException \InvalidArgumentException
-     */
     public function testLoadFromEventPayloadWithWrongPayload () {
+        $this->expectException(\InvalidArgumentException::class);
         $client = self::mockHttpClient();
         $payload = new stdClass;
         MailgunMessage::loadFromEventPayload($client, $payload, "0000");
     }
 
 
 }