diff --git a/src/tests/Infrastructure/ActivesyncTest.php b/src/tests/Infrastructure/ActivesyncTest.php
index 6ecfdee6..ec7ed45e 100644
--- a/src/tests/Infrastructure/ActivesyncTest.php
+++ b/src/tests/Infrastructure/ActivesyncTest.php
@@ -1,934 +1,1118 @@
 <?php
 
 namespace Tests\Infrastructure;
 
 use App\Backends\Roundcube;
 use Tests\TestCase;
 use Illuminate\Support\Str;
 
 class ActivesyncTest extends TestCase
 {
     private static ?\GuzzleHttp\Client $client = null;
     private static ?\App\User $user = null;
     private static ?string $deviceId = null;
     private static ?string $deviceId2 = null;
 
     private static function toWbxml($xml)
     {
         $outputStream = fopen("php://temp", 'r+');
         $encoder = new \Syncroton_Wbxml_Encoder($outputStream, 'UTF-8', 3);
         $dom = new \DOMDocument();
         $dom->loadXML($xml);
         $encoder->encode($dom);
         rewind($outputStream);
         return stream_get_contents($outputStream);
     }
 
     private static function fromWbxml($binary)
     {
         $stream = fopen('php://memory', 'r+');
         fwrite($stream, $binary);
         rewind($stream);
         $decoder = new \Syncroton_Wbxml_Decoder($stream);
         return $decoder->decode();
     }
 
     private function request($request, $cmd, $deviceId = null)
     {
         $user = self::$user;
         if (!$deviceId) {
             $deviceId = self::$deviceId;
         }
         $body = self::toWbxml($request);
         return self::$client->request(
             'POST',
             "?Cmd={$cmd}&User={$user->email}&DeviceId={$deviceId}&DeviceType=iphone",
             [
                 'headers' => [
                     "Content-Type" => "application/vnd.ms-sync.wbxml",
                     'MS-ASProtocolVersion' => "14.0"
                 ],
                 'body' => $body
             ]
         );
     }
 
     private function xpath($dom)
     {
         $xpath = new \DOMXpath($dom);
         $xpath->registerNamespace("ns", $dom->documentElement->namespaceURI);
         $xpath->registerNamespace("Tasks", "uri:Tasks");
         return $xpath;
     }
 
 
     /**
      * {@inheritDoc}
      */
     public function setUp(): void
     {
         parent::setUp();
 
         if (!self::$deviceId) {
             // By always creating a new device we force syncroton to initialize.
             // Otherwise we work against uninitialized metadata (subscription states),
             // because the account has been removed, but syncroton doesn't reinitalize the metadata for known devices.
             self::$deviceId = (string) Str::uuid();
             self::$deviceId2 = (string) Str::uuid();
         }
 
         $deviceId = self::$deviceId;
         \config(['imap.default_folders' => [
             'Drafts' => [
                 'metadata' => [
                     '/private/vendor/kolab/folder-type' => 'mail.drafts',
                     '/private/vendor/kolab/activesync' => "{\"FOLDER\":{\"{$deviceId}\":{\"S\":1}}}"
                 ],
             ],
             'Calendar' => [
                 'metadata' => [
                     '/private/vendor/kolab/folder-type' => 'event.default',
                     '/private/vendor/kolab/activesync' => "{\"FOLDER\":{\"{$deviceId}\":{\"S\":1}}}"
                 ],
             ],
             'Tasks' => [
                 'metadata' => [
                     '/private/vendor/kolab/folder-type' => 'task.default',
                     '/private/vendor/kolab/activesync' => "{\"FOLDER\":{\"{$deviceId}\":{\"S\":1}}}"
                 ],
             ],
             'Contacts' => [
                 'metadata' => [
                     '/private/vendor/kolab/folder-type' => 'contact.default',
                     '/private/vendor/kolab/activesync' => "{\"FOLDER\":{\"{$deviceId}\":{\"S\":1}}}"
                 ],
             ],
         ]]);
 
         if (!self::$user) {
             self::$user = $this->getTestUser('activesynctest@kolab.org', ['password' => 'simple123'], true);
             //FIXME this shouldn't be required, but it seems to be.
             Roundcube::dbh()->table('kolab_cache_task')->truncate();
             Roundcube::dbh()->table('syncroton_folder')->truncate();
             // Roundcube::dbh()->table('syncroton_content')->truncate();
             // Roundcube::dbh()->table('syncroton_device')->truncate();
         }
         if (!self::$client) {
             self::$client = new \GuzzleHttp\Client([
                     'http_errors' => false, // No exceptions
                     'base_uri' => \config("services.activesync.uri"),
                     'verify' => false,
                     'auth' => [self::$user->email, 'simple123'],
                     'connect_timeout' => 10,
                     'timeout' => 10,
                     'headers' => [
                         "Content-Type" => "application/xml; charset=utf-8",
                         "Depth" => "1",
                     ]
             ]);
         }
     }
 
     public function testOptions()
     {
         $response = self::$client->request('OPTIONS', '');
         $this->assertEquals(200, $response->getStatusCode());
         $this->assertStringContainsString('14', $response->getHeader('MS-Server-ActiveSync')[0]);
         $this->assertStringContainsString('14.1', $response->getHeader('MS-ASProtocolVersions')[0]);
         $this->assertStringContainsString('FolderSync', $response->getHeader('MS-ASProtocolCommands')[0]);
     }
 
     public function testPartialCommand()
     {
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <FolderSync xmlns="uri:FolderHierarchy">
             <SyncKey>0</SyncKey>
         </FolderSync>
         EOF;
 
         $body = self::toWbxml($request);
         $deviceId = self::$deviceId;
         $user = self::$user;
         $response =  self::$client->request(
             'POST',
             "?Cmd=FolderSync&User={$user->email}&DeviceId={$deviceId}&DeviceType=iphone",
             [
                 'headers' => [
                     "Content-Type" => "application/vnd.ms-sync.wbxml",
                     'MS-ASProtocolVersion' => "14.0"
                 ],
                 //Truncated body
                 'body' => substr($body, 0, strlen($body) / 2)
             ]
         );
 
         $this->assertEquals(500, $response->getStatusCode());
     }
 
     public function testList()
     {
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <FolderSync xmlns="uri:FolderHierarchy">
             <SyncKey>0</SyncKey>
         </FolderSync>
         EOF;
 
         $response = $this->request($request, 'FolderSync');
         $this->assertEquals(200, $response->getStatusCode());
         $dom = self::fromWbxml($response->getBody());
         $xml = $dom->saveXML();
 
         $this->assertStringContainsString('INBOX', $xml);
         // The hash is based on the name, so it's always the same
         $inboxId = '38b950ebd62cd9a66929c89615d0fc04';
         $this->assertStringContainsString($inboxId, $xml);
         $this->assertStringContainsString('Drafts', $xml);
         $this->assertStringContainsString('Calendar', $xml);
         $this->assertStringContainsString('Tasks', $xml);
         $this->assertStringContainsString('Contacts', $xml);
 
         // Find the inbox for the next step
         // $collectionIds = $dom->getElementsByTagName('ServerId');
         // $inboxId = $collectionIds[0]->nodeValue;
 
         return $inboxId;
     }
 
     /**
     * @depends testList
     */
     public function testInitialSync($inboxId)
     {
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase">
             <Collections>
                 <Collection>
                     <SyncKey>0</SyncKey>
                     <CollectionId>{$inboxId}</CollectionId>
                     <DeletesAsMoves>0</DeletesAsMoves>
                     <GetChanges>0</GetChanges>
                     <WindowSize>512</WindowSize>
                     <Options>
                         <FilterType>0</FilterType>
                         <BodyPreference xmlns="uri:AirSyncBase">
                             <Type>1</Type>
                             <AllOrNone>1</AllOrNone>
                         </BodyPreference>
                     </Options>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
 
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
         $dom = self::fromWbxml($response->getBody());
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $collections = $dom->getElementsByTagName('Collection');
         $this->assertEquals(1, $collections->length);
         $collection = $collections->item(0);
         $this->assertEquals("Class", $collection->childNodes->item(0)->nodeName);
         $this->assertEquals("Email", $collection->childNodes->item(0)->nodeValue);
         $this->assertEquals("SyncKey", $collection->childNodes->item(1)->nodeName);
         $this->assertEquals("1", $collection->childNodes->item(1)->nodeValue);
         $this->assertEquals("Status", $collection->childNodes->item(3)->nodeName);
         $this->assertEquals("1", $collection->childNodes->item(3)->nodeValue);
         return $inboxId;
     }
 
     /**
     * @depends testInitialSync
     */
     public function testAdd($inboxId)
     {
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase">
             <Collections>
                 <Collection>
                     <SyncKey>1</SyncKey>
                     <CollectionId>{$inboxId}</CollectionId>
                     <DeletesAsMoves>0</DeletesAsMoves>
                     <GetChanges>0</GetChanges>
                     <WindowSize>512</WindowSize>
                     <Options>
                         <FilterType>0</FilterType>
                         <BodyPreference xmlns="uri:AirSyncBase">
                             <Type>1</Type>
                             <AllOrNone>1</AllOrNone>
                         </BodyPreference>
                     </Options>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
 
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
         // We expect an empty response without a change
         $this->assertEquals(0, $response->getBody()->getSize());
     }
 
     /**
     * @depends testList
     */
     public function testSyncTasks()
     {
         $tasksId = "90335880f65deff6e521acea2b71a773";
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase">
             <Collections>
                 <Collection>
                     <SyncKey>0</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <DeletesAsMoves>0</DeletesAsMoves>
                     <GetChanges>0</GetChanges>
                     <WindowSize>512</WindowSize>
                     <Options>
                         <FilterType>0</FilterType>
                         <BodyPreference xmlns="uri:AirSyncBase">
                             <Type>1</Type>
                             <AllOrNone>1</AllOrNone>
                         </BodyPreference>
                     </Options>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
 
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
 
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase">
             <Collections>
                 <Collection>
                     <SyncKey>1</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <DeletesAsMoves>0</DeletesAsMoves>
                     <GetChanges>0</GetChanges>
                     <WindowSize>512</WindowSize>
                     <Options>
                         <FilterType>0</FilterType>
                         <BodyPreference xmlns="uri:AirSyncBase">
                             <Type>1</Type>
                             <AllOrNone>1</AllOrNone>
                         </BodyPreference>
                     </Options>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
 
         return $tasksId;
     }
 
     /**
     * @depends testSyncTasks
     */
     public function testAddTask($tasksId)
     {
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>1</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <Commands>
                         <Add>
                             <ClientId>clientId1</ClientId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task1</Subject>
                                 <Complete xmlns="uri:Tasks">0</Complete>
                                 <DueDate xmlns="uri:Tasks">2020-11-04T00:00:00.000Z</DueDate>
                                 <UtcDueDate xmlns="uri:Tasks">2020-11-03T23:00:00.000Z</UtcDueDate>
                             </ApplicationData>
                         </Add>
                     </Commands>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
 
         $dom = self::fromWbxml($response->getBody());
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $collections = $dom->getElementsByTagName('Collection');
         $this->assertEquals(1, $collections->length);
         $collection = $collections->item(0);
         $this->assertEquals("Class", $collection->childNodes->item(0)->nodeName);
         $this->assertEquals("Tasks", $collection->childNodes->item(0)->nodeValue);
 
         $this->assertEquals("SyncKey", $collection->childNodes->item(1)->nodeName);
         $this->assertEquals("2", $collection->childNodes->item(1)->nodeValue);
 
         $this->assertEquals("Status", $collection->childNodes->item(3)->nodeName);
         $this->assertEquals("1", $collection->childNodes->item(3)->nodeValue);
 
         $xpath = $this->xpath($dom);
         $add = $xpath->query("//ns:Responses/ns:Add");
         $this->assertEquals(1, $add->length);
         $this->assertEquals("clientId1", $xpath->query("//ns:Responses/ns:Add/ns:ClientId")->item(0)->nodeValue);
         $this->assertEquals(0, $xpath->query("//ns:Commands")->length);
         return [
             'collectionId' => $tasksId,
             'serverId1' => $xpath->query("//ns:Responses/ns:Add/ns:ServerId")->item(0)->nodeValue
         ];
     }
 
     /**
     * Re-issuing the same command should not result in the sync key being invalidated.
     *
     * @depends testAddTask
     */
     public function testReAddTask($result)
     {
         $tasksId = $result['collectionId'];
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>1</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <Commands>
                         <Add>
                             <ClientId>clientId1</ClientId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task1</Subject>
                                 <Complete xmlns="uri:Tasks">0</Complete>
                                 <DueDate xmlns="uri:Tasks">2020-11-04T00:00:00.000Z</DueDate>
                                 <UtcDueDate xmlns="uri:Tasks">2020-11-03T23:00:00.000Z</UtcDueDate>
                             </ApplicationData>
                         </Add>
                     </Commands>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
 
         $dom = self::fromWbxml($response->getBody());
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $collections = $dom->getElementsByTagName('Collection');
         $this->assertEquals(1, $collections->length);
         $collection = $collections->item(0);
         $this->assertEquals("Class", $collection->childNodes->item(0)->nodeName);
         $this->assertEquals("Tasks", $collection->childNodes->item(0)->nodeValue);
 
         $this->assertEquals("SyncKey", $collection->childNodes->item(1)->nodeName);
         $this->assertEquals("2", $collection->childNodes->item(1)->nodeValue);
 
         $this->assertEquals("Status", $collection->childNodes->item(3)->nodeName);
         $this->assertEquals("1", $collection->childNodes->item(3)->nodeValue);
 
         $xpath = $this->xpath($dom);
         $add = $xpath->query("//ns:Responses/ns:Add");
         $this->assertEquals(1, $add->length);
         $this->assertEquals("clientId1", $xpath->query("//ns:Responses/ns:Add/ns:ClientId")->item(0)->nodeValue);
         $this->assertEquals(0, $xpath->query("//ns:Commands")->length);
         return [
             'collectionId' => $tasksId,
             'serverId1' => $xpath->query("//ns:Responses/ns:Add/ns:ServerId")->item(0)->nodeValue
         ];
     }
 
     /**
     * Make sure we can continue with the sync after the previous hickup, also include a modification.
     *
     * @depends testAddTask
     */
     public function testAddTaskContinued($result)
     {
         $tasksId = $result['collectionId'];
         $serverId = $result['serverId1'];
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>2</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <Commands>
                         <Add>
                             <ClientId>clientId2</ClientId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task2</Subject>
                                 <Complete xmlns="uri:Tasks">0</Complete>
                                 <DueDate xmlns="uri:Tasks">2020-11-04T00:00:00.000Z</DueDate>
                                 <UtcDueDate xmlns="uri:Tasks">2020-11-03T23:00:00.000Z</UtcDueDate>
                             </ApplicationData>
                         </Add>
                         <Add>
                             <ClientId>clientId3</ClientId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task3</Subject>
                                 <Complete xmlns="uri:Tasks">0</Complete>
                                 <DueDate xmlns="uri:Tasks">2020-11-04T00:00:00.000Z</DueDate>
                                 <UtcDueDate xmlns="uri:Tasks">2020-11-03T23:00:00.000Z</UtcDueDate>
                             </ApplicationData>
                         </Add>
                         <Change>
                             <ServerId>{$serverId}</ServerId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task4</Subject>
                             </ApplicationData>
                         </Change>
                     </Commands>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
 
         $dom = self::fromWbxml($response->getBody());
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $collections = $dom->getElementsByTagName('Collection');
         $this->assertEquals(1, $collections->length);
         $collection = $collections->item(0);
         $this->assertEquals("Class", $collection->childNodes->item(0)->nodeName);
         $this->assertEquals("Tasks", $collection->childNodes->item(0)->nodeValue);
 
         $this->assertEquals("SyncKey", $collection->childNodes->item(1)->nodeName);
         $this->assertEquals("3", $collection->childNodes->item(1)->nodeValue);
 
         $this->assertEquals("Status", $collection->childNodes->item(3)->nodeName);
         $this->assertEquals("1", $collection->childNodes->item(3)->nodeValue);
 
         $xpath = $this->xpath($dom);
         $add = $xpath->query("//ns:Responses/ns:Add");
         $this->assertEquals(2, $add->length);
         $this->assertEquals("clientId2", $xpath->query("//ns:Responses/ns:Add/ns:ClientId")->item(0)->nodeValue);
         $this->assertEquals("clientId3", $xpath->query("//ns:Responses/ns:Add/ns:ClientId")->item(1)->nodeValue);
         $this->assertEquals(0, $xpath->query("//ns:Commands")->length);
 
         // The server does not have to inform about a successful change
         $change = $xpath->query("//ns:Responses/ns:Change");
         $this->assertEquals(0, $change->length);
 
         return [
             'collectionId' => $tasksId,
             'serverId1' => $xpath->query("//ns:Responses/ns:Add/ns:ServerId")->item(0)->nodeValue,
             'serverId2' => $xpath->query("//ns:Responses/ns:Add/ns:ServerId")->item(1)->nodeValue
         ];
     }
 
     /**
     * Perform another duplicate request.
     *
     * @depends testAddTaskContinued
     */
     public function testAddTaskContinuedAgain($result)
     {
         $tasksId = $result['collectionId'];
         $serverId = $result['serverId1'];
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>2</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <Commands>
                         <Add>
                             <ClientId>clientId2</ClientId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task2</Subject>
                                 <Complete xmlns="uri:Tasks">0</Complete>
                                 <DueDate xmlns="uri:Tasks">2020-11-04T00:00:00.000Z</DueDate>
                                 <UtcDueDate xmlns="uri:Tasks">2020-11-03T23:00:00.000Z</UtcDueDate>
                             </ApplicationData>
                         </Add>
                         <Add>
                             <ClientId>clientId3</ClientId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task3</Subject>
                                 <Complete xmlns="uri:Tasks">0</Complete>
                                 <DueDate xmlns="uri:Tasks">2020-11-04T00:00:00.000Z</DueDate>
                                 <UtcDueDate xmlns="uri:Tasks">2020-11-03T23:00:00.000Z</UtcDueDate>
                             </ApplicationData>
                         </Add>
                         <Change>
                             <ServerId>{$serverId}</ServerId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task4</Subject>
                             </ApplicationData>
                         </Change>
                     </Commands>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
 
         $dom = self::fromWbxml($response->getBody());
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $collections = $dom->getElementsByTagName('Collection');
         $this->assertEquals(1, $collections->length);
         $collection = $collections->item(0);
         $this->assertEquals("Class", $collection->childNodes->item(0)->nodeName);
         $this->assertEquals("Tasks", $collection->childNodes->item(0)->nodeValue);
 
         $this->assertEquals("SyncKey", $collection->childNodes->item(1)->nodeName);
         $this->assertEquals("3", $collection->childNodes->item(1)->nodeValue);
 
         $this->assertEquals("Status", $collection->childNodes->item(3)->nodeName);
         $this->assertEquals("1", $collection->childNodes->item(3)->nodeValue);
 
         $xpath = $this->xpath($dom);
         print($dom->saveXML());
         $add = $xpath->query("//ns:Responses/ns:Add");
         $this->assertEquals(2, $add->length);
 
         $this->assertEquals("clientId2", $xpath->query("//ns:Responses/ns:Add/ns:ClientId")->item(0)->nodeValue);
         $this->assertEquals(
             $result['serverId1'],
             $xpath->query("//ns:Responses/ns:Add/ns:ServerId")->item(0)->nodeValue
         );
 
         $this->assertEquals("clientId3", $xpath->query("//ns:Responses/ns:Add/ns:ClientId")->item(1)->nodeValue);
         $this->assertEquals(
             $result['serverId2'],
             $xpath->query("//ns:Responses/ns:Add/ns:ServerId")->item(1)->nodeValue
         );
 
         // The server does not have to inform about a successful change
         $change = $xpath->query("//ns:Responses/ns:Change");
         $this->assertEquals(0, $change->length);
 
         $this->assertEquals(0, $xpath->query("//ns:Commands")->length);
 
         return [
             'collectionId' => $tasksId,
             'serverId2' => $xpath->query("//ns:Responses/ns:Add/ns:ServerId")->item(1)->nodeValue
         ];
     }
 
     /**
     * Test a sync key that shouldn't exist yet.
     * @depends testSyncTasks
     */
     public function testInvalidSyncKey($tasksId)
     {
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>4</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <Commands>
                         <Add>
                             <ClientId>clientId999</ClientId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task1</Subject>
                                 <Complete xmlns="uri:Tasks">0</Complete>
                                 <DueDate xmlns="uri:Tasks">2020-11-04T00:00:00.000Z</DueDate>
                                 <UtcDueDate xmlns="uri:Tasks">2020-11-03T23:00:00.000Z</UtcDueDate>
                             </ApplicationData>
                         </Add>
                     </Commands>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
 
         $dom = self::fromWbxml($response->getBody());
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("3", $status[0]->nodeValue);
         //After this we have to start from scratch
     }
 
     /**
     * Test fetching changes with a second device
     * @depends testAddTaskContinuedAgain
     */
     public function testFetchTasks($result)
     {
         $tasksId = $result['collectionId'];
         $serverId = $result['serverId2'];
         // Initialize the second device
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <FolderSync xmlns="uri:FolderHierarchy">
             <SyncKey>0</SyncKey>
         </FolderSync>
         EOF;
 
         $response = $this->request($request, 'FolderSync', self::$deviceId2);
         $this->assertEquals(200, $response->getStatusCode());
 
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>0</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <DeletesAsMoves>0</DeletesAsMoves>
                     <WindowSize>512</WindowSize>
                     <Options>
                         <FilterType>0</FilterType>
                         <MIMESupport>2</MIMESupport>
                         <MIMETruncation>8</MIMETruncation>
                         <BodyPreference xmlns="uri:AirSyncBase">
                             <Type>4</Type>
                             <AllOrNone>1</AllOrNone>
                         </BodyPreference>
                     </Options>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync', self::$deviceId2);
         $this->assertEquals(200, $response->getStatusCode());
         $dom = self::fromWbxml($response->getBody());
         print($dom->saveXML());
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
 
         // Fetch the content
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>1</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync', self::$deviceId2);
         $this->assertEquals(200, $response->getStatusCode());
 
         $dom = self::fromWbxml($response->getBody());
         print($dom->saveXML());
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $xpath = $this->xpath($dom);
         $add = $xpath->query("//ns:Commands/ns:Add");
         $this->assertEquals(3, $add->length);
 
 
         //Resend the same command
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>1</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync', self::$deviceId2);
         $this->assertEquals(200, $response->getStatusCode());
 
         $dom = self::fromWbxml($response->getBody());
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $xpath = $this->xpath($dom);
         $add = $xpath->query("//ns:Commands/ns:Add");
         $this->assertEquals(3, $add->length);
 
         // Add another entry, delete an entry, with the original device (we have to init first again)
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>0</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <DeletesAsMoves>0</DeletesAsMoves>
                     <WindowSize>512</WindowSize>
                     <Options>
                         <FilterType>0</FilterType>
                         <MIMESupport>2</MIMESupport>
                         <MIMETruncation>8</MIMETruncation>
                         <BodyPreference xmlns="uri:AirSyncBase">
                             <Type>4</Type>
                             <AllOrNone>1</AllOrNone>
                         </BodyPreference>
                     </Options>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
 
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>1</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
 
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>2</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                     <Commands>
                         <Add>
                             <ClientId>clientId4</ClientId>
                             <ApplicationData>
                                 <Subject xmlns="uri:Tasks">task4</Subject>
                                 <Complete xmlns="uri:Tasks">0</Complete>
                                 <DueDate xmlns="uri:Tasks">2020-11-04T00:00:00.000Z</DueDate>
                                 <UtcDueDate xmlns="uri:Tasks">2020-11-03T23:00:00.000Z</UtcDueDate>
                             </ApplicationData>
                         </Add>
                         <Delete>
                             <ServerId>{$serverId}</ServerId>
                         </Delete>
                     </Commands>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync');
         $this->assertEquals(200, $response->getStatusCode());
         $dom = self::fromWbxml($response->getBody());
 
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $xpath = $this->xpath($dom);
         $add = $xpath->query("//ns:Responses/ns:Add");
         $this->assertEquals(1, $add->length);
         // Delete does not have to be confirmed according to spec
         $delete = $xpath->query("//ns:Responses/ns:Delete");
         $this->assertEquals(0, $delete->length);
 
         // And fetch the changes
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>2</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync', self::$deviceId2);
         $this->assertEquals(200, $response->getStatusCode());
 
         $dom = self::fromWbxml($response->getBody());
         // print("=====\n");
         // print($dom->saveXML());
         // print("=====\n");
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $xpath = $this->xpath($dom);
         $add = $xpath->query("//ns:Commands/ns:Add");
         $this->assertEquals(1, $add->length);
         $delete = $xpath->query("//ns:Commands/ns:Delete");
         $this->assertEquals(1, $delete->length);
 
         // and finally refetch the same changes
         $request = <<<EOF
         <?xml version="1.0" encoding="utf-8"?>
         <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
         <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
             <Collections>
                 <Collection>
                     <SyncKey>2</SyncKey>
                     <CollectionId>{$tasksId}</CollectionId>
                 </Collection>
             </Collections>
             <WindowSize>16</WindowSize>
         </Sync>
         EOF;
         $response = $this->request($request, 'Sync', self::$deviceId2);
         $this->assertEquals(200, $response->getStatusCode());
 
         $dom = self::fromWbxml($response->getBody());
         // print("=====\n");
         // print($dom->saveXML());
         // print("=====\n");
         $status = $dom->getElementsByTagName('Status');
         $this->assertEquals("1", $status[0]->nodeValue);
         $xpath = $this->xpath($dom);
         $add = $xpath->query("//ns:Commands/ns:Add");
         $this->assertEquals(1, $add->length);
         //FIXME we currently miss deletions.
         $delete = $xpath->query("//ns:Commands/ns:Delete");
         $this->assertEquals(0, $delete->length);
     }
 
+    /**
+    * @depends testList
+    */
+    public function testSyncCalendar()
+    {
+        $tasksId = "cca1b81c734abbcd669bea90d23e08ae";
+        $request = <<<EOF
+        <?xml version="1.0" encoding="utf-8"?>
+        <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
+        <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase">
+            <Collections>
+                <Collection>
+                    <SyncKey>0</SyncKey>
+                    <CollectionId>{$tasksId}</CollectionId>
+                    <DeletesAsMoves>0</DeletesAsMoves>
+                    <GetChanges>0</GetChanges>
+                    <WindowSize>512</WindowSize>
+                    <Options>
+                        <FilterType>0</FilterType>
+                        <BodyPreference xmlns="uri:AirSyncBase">
+                            <Type>1</Type>
+                            <AllOrNone>1</AllOrNone>
+                        </BodyPreference>
+                    </Options>
+                </Collection>
+            </Collections>
+            <WindowSize>16</WindowSize>
+        </Sync>
+        EOF;
+
+        $response = $this->request($request, 'Sync');
+        $this->assertEquals(200, $response->getStatusCode());
+
+        $request = <<<EOF
+        <?xml version="1.0" encoding="utf-8"?>
+        <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
+        <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase">
+            <Collections>
+                <Collection>
+                    <SyncKey>1</SyncKey>
+                    <CollectionId>{$tasksId}</CollectionId>
+                    <DeletesAsMoves>0</DeletesAsMoves>
+                    <GetChanges>0</GetChanges>
+                    <WindowSize>512</WindowSize>
+                    <Options>
+                        <FilterType>0</FilterType>
+                        <BodyPreference xmlns="uri:AirSyncBase">
+                            <Type>1</Type>
+                            <AllOrNone>1</AllOrNone>
+                        </BodyPreference>
+                    </Options>
+                </Collection>
+            </Collections>
+            <WindowSize>16</WindowSize>
+        </Sync>
+        EOF;
+        $response = $this->request($request, 'Sync');
+        $this->assertEquals(200, $response->getStatusCode());
+
+        return $tasksId;
+    }
+
+    /**
+    * @depends testSyncCalendar
+    */
+    public function testAddEvent($tasksId)
+    {
+        $request = <<<EOF
+        <?xml version="1.0" encoding="utf-8"?>
+        <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
+        <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
+            <Collections>
+                <Collection>
+                    <SyncKey>1</SyncKey>
+                    <CollectionId>{$tasksId}</CollectionId>
+                    <Commands>
+                        <Add>
+                            <ClientId>clientId1</ClientId>
+                            <ApplicationData>
+                                <StartTime xmlns="uri:Calendar">20230719T200032Z</StartTime>
+                                <BusyStatus xmlns="uri:Calendar">2</BusyStatus>
+                                <DtStamp xmlns="uri:Calendar">20230719T194232Z</DtStamp>
+                                <EndTime xmlns="uri:Calendar">20230719T203032Z</EndTime>
+                                <UID xmlns="uri:Calendar">046f2e01-e8d0-47c6-a607-ba360251761d</UID>
+                                <OrganizerEmail xmlns="uri:Calendar">activesynctest@kolab.org</OrganizerEmail>
+                                <MeetingStatus xmlns="uri:Calendar">0</MeetingStatus>
+                                <ResponseRequested xmlns="uri:Calendar">0</ResponseRequested>
+                            </ApplicationData>
+                        </Add>
+                    </Commands>
+                </Collection>
+            </Collections>
+            <WindowSize>16</WindowSize>
+        </Sync>
+        EOF;
+        $response = $this->request($request, 'Sync');
+        $this->assertEquals(200, $response->getStatusCode());
+
+        $dom = self::fromWbxml($response->getBody());
+        print($dom->saveXML());
+        $status = $dom->getElementsByTagName('Status');
+        $this->assertEquals("1", $status[0]->nodeValue);
+        $collections = $dom->getElementsByTagName('Collection');
+        $this->assertEquals(1, $collections->length);
+        $collection = $collections->item(0);
+        $this->assertEquals("Class", $collection->childNodes->item(0)->nodeName);
+        $this->assertEquals("Calendar", $collection->childNodes->item(0)->nodeValue);
+
+        $this->assertEquals("SyncKey", $collection->childNodes->item(1)->nodeName);
+        $this->assertEquals("2", $collection->childNodes->item(1)->nodeValue);
+
+        $this->assertEquals("Status", $collection->childNodes->item(3)->nodeName);
+        $this->assertEquals("1", $collection->childNodes->item(3)->nodeValue);
+
+        $xpath = $this->xpath($dom);
+        $add = $xpath->query("//ns:Responses/ns:Add");
+        $this->assertEquals(1, $add->length);
+        $this->assertEquals("clientId1", $xpath->query("//ns:Responses/ns:Add/ns:ClientId")->item(0)->nodeValue);
+        // $this->assertEquals(0, $xpath->query("//ns:Commands")->length);
+        return [
+            'collectionId' => $tasksId,
+            'serverId1' => $xpath->query("//ns:Responses/ns:Add/ns:ServerId")->item(0)->nodeValue
+        ];
+    }
+
+    /**
+    * @depends testAddEvent
+    */
+    public function testReaddEvent($result)
+    {
+        $tasksId = $result['collectionId'];
+        $request = <<<EOF
+        <?xml version="1.0" encoding="utf-8"?>
+        <!DOCTYPE AirSync PUBLIC "-//AIRSYNC//DTD AirSync//EN" "http://www.microsoft.com/">
+        <Sync xmlns="uri:AirSync" xmlns:AirSyncBase="uri:AirSyncBase" xmlns:Tasks="uri:Tasks">
+            <Collections>
+                <Collection>
+                    <SyncKey>2</SyncKey>
+                    <CollectionId>{$tasksId}</CollectionId>
+                    <Commands>
+                        <Add>
+                            <ClientId>clientId1</ClientId>
+                            <ApplicationData>
+                                <StartTime xmlns="uri:Calendar">20230719T200032Z</StartTime>
+                                <BusyStatus xmlns="uri:Calendar">2</BusyStatus>
+                                <DtStamp xmlns="uri:Calendar">20230719T194232Z</DtStamp>
+                                <EndTime xmlns="uri:Calendar">20230719T203032Z</EndTime>
+                                <UID xmlns="uri:Calendar">046f2e01-e8d0-47c6-a607-ba360251761d</UID>
+                                <OrganizerEmail xmlns="uri:Calendar">activesynctest@kolab.org</OrganizerEmail>
+                                <MeetingStatus xmlns="uri:Calendar">0</MeetingStatus>
+                                <ResponseRequested xmlns="uri:Calendar">0</ResponseRequested>
+                            </ApplicationData>
+                        </Add>
+                    </Commands>
+                </Collection>
+            </Collections>
+            <WindowSize>16</WindowSize>
+        </Sync>
+        EOF;
+        $response = $this->request($request, 'Sync');
+        $this->assertEquals(200, $response->getStatusCode());
+
+        $dom = self::fromWbxml($response->getBody());
+        print($dom->saveXML());
+        $status = $dom->getElementsByTagName('Status');
+        $this->assertEquals("1", $status[0]->nodeValue);
+        $collections = $dom->getElementsByTagName('Collection');
+        $this->assertEquals(1, $collections->length);
+        $collection = $collections->item(0);
+        $this->assertEquals("Class", $collection->childNodes->item(0)->nodeName);
+        $this->assertEquals("Calendar", $collection->childNodes->item(0)->nodeValue);
+
+        $this->assertEquals("SyncKey", $collection->childNodes->item(1)->nodeName);
+        $this->assertEquals("3", $collection->childNodes->item(1)->nodeValue);
+
+        $this->assertEquals("Status", $collection->childNodes->item(3)->nodeName);
+        $this->assertEquals("1", $collection->childNodes->item(3)->nodeValue);
+
+        $xpath = $this->xpath($dom);
+        $add = $xpath->query("//ns:Responses/ns:Add");
+        $this->assertEquals(1, $add->length);
+        $this->assertEquals("clientId1", $xpath->query("//ns:Responses/ns:Add/ns:ClientId")->item(0)->nodeValue);
+        $this->assertEquals(0, $xpath->query("//ns:Commands")->length);
+    }
 
     /**
      * @doesNotPerformAssertions
      */
     public function testCleanup(): void
     {
         $this->deleteTestUser(self::$user->email);
     }
 }