diff --git a/src/Helper/EntityHelper.php b/src/Helper/EntityHelper.php
index 5cfad30..5ffed7c 100644
--- a/src/Helper/EntityHelper.php
+++ b/src/Helper/EntityHelper.php
@@ -35,13 +35,25 @@ public static function createSerializer(): Serializer
         return self::$serializer;
     }
 
+    public static function formatDateCreated(string $dateCreated): string
+    {
+        return  (new \DateTime($dateCreated))->format('Y-m-d\TH:i:s');
+    }
+
     /**
      * @return mixed
      */
     public static function deserializeXml(string $class, string $xml)
     {
         $serializer = self::createSerializer()->getSerializer();
-        return $serializer->deserialize($xml, $class, 'xml');
+
+        $simpleXml = new \SimpleXMLElement($xml);
+
+        if (property_exists($simpleXml, 'Header')) {
+            $simpleXml->Header->DateCreated = self::formatDateCreated((string) $simpleXml->Header->DateCreated);
+        }
+
+        return $serializer->deserialize((string) $simpleXml->saveXML(), $class, 'xml');
     }
 
     /**
diff --git a/src/Helper/XmlHelper.php b/src/Helper/XmlHelper.php
index 3c8f2b2..8483f64 100644
--- a/src/Helper/XmlHelper.php
+++ b/src/Helper/XmlHelper.php
@@ -101,7 +101,7 @@ public static function fetchChildNodes(string $node, \SimpleXMLElement $xml): ar
 
         if (property_exists($xml, 'Header')) {
             $data['Header'] = (array) $xml->Header;
-            $data['Header']['DateCreated'] = (new \DateTime($data['Header']['DateCreated']))->format('Y-m-d\TH:i:s');
+            $data['Header']['DateCreated'] = EntityHelper::formatDateCreated($data['Header']['DateCreated']);
         }
 
         return $data;
diff --git a/tests/Integration/Component/CloudLicenseOrderTest.php b/tests/Integration/Component/CloudLicenseOrderTest.php
index 41a8515..20845d1 100644
--- a/tests/Integration/Component/CloudLicenseOrderTest.php
+++ b/tests/Integration/Component/CloudLicenseOrderTest.php
@@ -30,11 +30,12 @@ public function create(): void
             'Test',
             'john@doe.com'
         );
+
         $contact = $officeClient->contact->agreement->create(
-            'john',
-            'doe',
-            'john@doe.com',
-            '12345',
+            'Sandwave',
+            'Test',
+            'willem@sandwave.io',
+            '0622029880',
             new \DateTime()
         );
 
@@ -42,7 +43,7 @@ public function create(): void
             $tenant,
             $contact,
             '507201',
-            '120A00064B',
+            '120A00385B',
             1
         );
 
diff --git a/tests/Integration/Component/OrderModifyQuantityTest.php b/tests/Integration/Component/OrderModifyQuantityTest.php
index 916781a..64e5920 100644
--- a/tests/Integration/Component/OrderModifyQuantityTest.php
+++ b/tests/Integration/Component/OrderModifyQuantityTest.php
@@ -25,8 +25,8 @@ public function create(): void
         $officeClient = new OfficeClient('example.com', 'test', 'test', ['handler' => $stack]);
 
         $response = $officeClient->order->modify(
-            10035367,
-            0,
+            10333119,
+            2,
             false,
             '123'
         );
diff --git a/tests/Integration/Component/PreferenceHeaderDateTest.php b/tests/Integration/Component/PreferenceHeaderDateTest.php
new file mode 100644
index 0000000..b98866c
--- /dev/null
+++ b/tests/Integration/Component/PreferenceHeaderDateTest.php
@@ -0,0 +1,71 @@
+<?php declare(strict_types = 1);
+
+namespace Integration\Webhook;
+
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Response;
+use PHPUnit\Framework\Assert;
+use PHPUnit\Framework\TestCase;
+use SandwaveIo\Office365\Entity\Customer;
+use SandwaveIo\Office365\Entity\OrderModifyQuantity;
+use SandwaveIo\Office365\Enum\Event;
+use SandwaveIo\Office365\Library\Observer\Customer\CustomerObserverInterface;
+use SandwaveIo\Office365\Library\Observer\Order\OrderModifyQuantityObserverInterface;
+use SandwaveIo\Office365\Library\Observer\Status\Status;
+use SandwaveIo\Office365\Office\OfficeClient;
+
+final class PreferenceHeaderDateTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function deserializeArrayPrefHeaderDate(): void
+    {
+        $mockHandler = new MockHandler(
+            [new Response(200, [], (string) file_get_contents(__DIR__ . '/../Data/Request/NewCustomerRequest.xml'))]
+        );
+
+        $stack = HandlerStack::create($mockHandler);
+        $client = new OfficeClient('example.com', 'test', 'test', ['handler' => $stack]);
+
+        $client->webhook->addEventSubscriber(Event::CUSTOMER_CREATE, new class() implements CustomerObserverInterface {
+            public function execute(Customer $customer, ?Status $status): void
+            {
+                if ($customer->getHeader() !== null) {
+                    Assert::assertSame('2022-02-15 15:14:09', $customer->getHeader()->getDateCreated()->format('Y-m-d H:i:s'));
+                }
+            }
+        });
+
+        $client->webhook->process(
+            (string) file_get_contents(__DIR__ . '/../Data/Response/NewCustomerResponse_V3.xml')
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function deserializeXmlPrefHeaderDate(): void
+    {
+        $mockHandler = new MockHandler(
+            [new Response(200, [], (string) file_get_contents(__DIR__ . '/../Data/Request/NewCustomerRequest.xml'))]
+        );
+
+        $stack = HandlerStack::create($mockHandler);
+        $client = new OfficeClient('example.com', 'test', 'test', ['handler' => $stack]);
+
+        $client->webhook->addEventSubscriber(Event::ORDER_MODIFY_QUANTITY, new class() implements OrderModifyQuantityObserverInterface {
+            public function execute(OrderModifyQuantity $order, ?Status $status): void
+            {
+                if ($order->getHeader() !== null) {
+                    Assert::assertSame('2022-03-07 12:09:56', $order->getHeader()->getDateCreated()->format('Y-m-d H:i:s'));
+                }
+            }
+        });
+
+        $client->webhook->process(
+            (string) file_get_contents(__DIR__ . '/../Data/Response/ModifyOrderQuantityResponse.xml')
+        );
+    }
+}
diff --git a/tests/Integration/Webhook/DateTest.php b/tests/Integration/Webhook/DateTest.php
new file mode 100644
index 0000000..bb1d21a
--- /dev/null
+++ b/tests/Integration/Webhook/DateTest.php
@@ -0,0 +1,71 @@
+<?php declare(strict_types = 1);
+
+namespace Integration\Webhook;
+
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Response;
+use PHPUnit\Framework\Assert;
+use PHPUnit\Framework\TestCase;
+use SandwaveIo\Office365\Entity\Customer;
+use SandwaveIo\Office365\Entity\OrderModifyQuantity;
+use SandwaveIo\Office365\Enum\Event;
+use SandwaveIo\Office365\Library\Observer\Customer\CustomerObserverInterface;
+use SandwaveIo\Office365\Library\Observer\Order\OrderModifyQuantityObserverInterface;
+use SandwaveIo\Office365\Library\Observer\Status\Status;
+use SandwaveIo\Office365\Office\OfficeClient;
+
+final class DateTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function deserializeArrayPrefHeaderDate(): void
+    {
+        $mockHandler = new MockHandler(
+            [new Response(200, [], (string) file_get_contents(__DIR__ . '/../Data/Request/NewCustomerRequest.xml'))]
+        );
+
+        $stack = HandlerStack::create($mockHandler);
+        $client = new OfficeClient('example.com', 'test', 'test', ['handler' => $stack]);
+
+        $client->webhook->addEventSubscriber(Event::CUSTOMER_CREATE, new class() implements CustomerObserverInterface {
+            public function execute(Customer $customer, ?Status $status): void
+            {
+                if ($customer->getHeader() !== null) {
+                    Assert::assertSame('2022-02-15 15:14:09', $customer->getHeader()->getDateCreated()->format('Y-m-d H:i:s'));
+                }
+            }
+        });
+
+        $client->webhook->process(
+            (string) file_get_contents(__DIR__ . '/../Data/Response/NewCustomerResponse_V3.xml')
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function deserializeXmlPrefHeaderDate(): void
+    {
+        $mockHandler = new MockHandler(
+            [new Response(200, [], (string) file_get_contents(__DIR__ . '/../Data/Request/NewCustomerRequest.xml'))]
+        );
+
+        $stack = HandlerStack::create($mockHandler);
+        $client = new OfficeClient('example.com', 'test', 'test', ['handler' => $stack]);
+
+        $client->webhook->addEventSubscriber(Event::ORDER_MODIFY_QUANTITY, new class() implements OrderModifyQuantityObserverInterface {
+            public function execute(OrderModifyQuantity $order, ?Status $status): void
+            {
+                if ($order->getHeader() !== null) {
+                    Assert::assertSame('2022-03-07 12:09:56', $order->getHeader()->getDateCreated()->format('Y-m-d H:i:s'));
+                }
+            }
+        });
+
+        $client->webhook->process(
+            (string) file_get_contents(__DIR__ . '/../Data/Response/ModifyOrderQuantityResponse.xml')
+        );
+    }
+}