diff --git a/lib/ext/Syncroton/Command/Options.php b/lib/ext/Syncroton/Command/Options.php
--- a/lib/ext/Syncroton/Command/Options.php
+++ b/lib/ext/Syncroton/Command/Options.php
@@ -26,8 +26,8 @@
     {
         // same header like Exchange 2xxx???
         return [
-            'MS-Server-ActiveSync'  => '14.00.0536.000',
-            'MS-ASProtocolVersions' => '2.5,12.0,12.1,14.0,14.1',
+            'MS-Server-ActiveSync'  => '16.00.0536.000',
+            'MS-ASProtocolVersions' => '2.5,12.0,12.1,14.0,14.1,16.0',
             'MS-ASProtocolCommands' => 'FolderCreate,FolderDelete,FolderSync,FolderUpdate,GetAttachment,GetItemEstimate,ItemOperations,MeetingResponse,MoveItems,Provision,ResolveRecipients,Ping,SendMail,Search,Settings,SmartForward,SmartReply,Sync,ValidateCert',
         ];
     }
diff --git a/lib/ext/Syncroton/Model/Email.php b/lib/ext/Syncroton/Model/Email.php
--- a/lib/ext/Syncroton/Model/Email.php
+++ b/lib/ext/Syncroton/Model/Email.php
@@ -19,6 +19,7 @@
  * @property    array                       $flag
  * @property    Syncroton_Model_EmailBody   $body
  * @property    array                       $cc
+ * @property    array                       $bcc
  * @property    array                       $to
  * @property    int                         $lastVerbExecuted
  * @property    DateTime                    $lastVerbExecutionTime
@@ -85,6 +86,7 @@
             'sender'                => ['type' => 'string', 'supportedSince' => '14.0'],
             'umCallerID'            => ['type' => 'string', 'supportedSince' => '14.0'],
             'umUserNotes'           => ['type' => 'string', 'supportedSince' => '14.0'],
+            'bcc'                   => ['type' => 'string', 'supportedSince' => '16.0'],
         ],
     ];
 }
diff --git a/lib/ext/Syncroton/Server.php b/lib/ext/Syncroton/Server.php
--- a/lib/ext/Syncroton/Server.php
+++ b/lib/ext/Syncroton/Server.php
@@ -138,7 +138,7 @@
             $requestBody = $this->_body;
         }
 
-        header("MS-Server-ActiveSync: 14.00.0536.000");
+        header("MS-Server-ActiveSync: 16.00.0536.000");
 
         // avoid sending HTTP header "Content-Type: text/html" for empty sync responses
         ini_set('default_mimetype', 'application/vnd.ms-sync.wbxml');
diff --git a/lib/ext/Syncroton/Wbxml/Dtd/ActiveSync/CodePage22.php b/lib/ext/Syncroton/Wbxml/Dtd/ActiveSync/CodePage22.php
--- a/lib/ext/Syncroton/Wbxml/Dtd/ActiveSync/CodePage22.php
+++ b/lib/ext/Syncroton/Wbxml/Dtd/ActiveSync/CodePage22.php
@@ -38,5 +38,8 @@
         'AccountId'             => 0x11,
         'FirstDayOfWeek'        => 0x12,
         'MeetingMessageType'    => 0x13,
+        'IsDraft'               => 0x15,
+        'Bcc'                   => 0x16,
+        'Send'                  => 0x17,
    ];
 }
diff --git a/lib/kolab_sync_data_email.php b/lib/kolab_sync_data_email.php
--- a/lib/kolab_sync_data_email.php
+++ b/lib/kolab_sync_data_email.php
@@ -35,6 +35,7 @@
      */
     protected $mapping = [
         'cc'                    => 'cc',
+        'bcc'                   => 'bcc',
         //'contentClass'          => 'contentclass',
         'dateReceived'          => 'internaldate',
         //'displayTo'             => 'displayto', //?
@@ -191,10 +192,11 @@
                     break;
 
                 case 'cc':
+                case 'bcc':
                 case 'to':
                 case 'replyto':
                 case 'from':
-                    $addresses = rcube_mime::decode_address_list($headers->$name, null, true, $headers->charset);
+                    $addresses = rcube_mime::decode_address_list($headers->get($name, false), null, true, $headers->charset);
 
                     foreach ($addresses as $idx => $part) {
                         // @FIXME: set name + address or address only?
diff --git a/lib/kolab_sync_message.php b/lib/kolab_sync_message.php
--- a/lib/kolab_sync_message.php
+++ b/lib/kolab_sync_message.php
@@ -212,9 +212,6 @@
             $headers['To'] = 'undisclosed-recipients:;';
         }
 
-        // remove Bcc header
-        unset($smtp_headers['Bcc']);
-
         // send message
         if (!is_object($rcube->smtp)) {
             $rcube->smtp_init(true);