diff --git a/calendar/inc/class.calendar_groupdav.inc.php b/calendar/inc/class.calendar_groupdav.inc.php
index 7e589fc421..0609529505 100644
--- a/calendar/inc/class.calendar_groupdav.inc.php
+++ b/calendar/inc/class.calendar_groupdav.inc.php
@@ -105,7 +105,7 @@ class calendar_groupdav extends groupdav_handler
 				);
 				if ($calendar_data)
 				{
-					$content = ExecMethod2('calendar.boical.exportVCal',array($event),'2.0','PUBLISH',false);
+					$content = ExecMethod2('calendar.boical.exportVCal',array($event),'2.0','PUBLISH',false,false);
 					$props[] = HTTP_WebDAV_Server::mkprop('getcontentlength',bytes($content));
 					$props[] = HTTP_WebDAV_Server::mkprop(groupdav::CALDAV,'calendar-data',$content);
 				}
@@ -246,7 +246,7 @@ class calendar_groupdav extends groupdav_handler
 		{
 			return $event;
 		}
-		$options['data'] = ExecMethod2('calendar.boical.exportVCal',array($event),'2.0','PUBLISH',false);
+		$options['data'] = ExecMethod2('calendar.boical.exportVCal',array($event),'2.0','PUBLISH',false,false);
 		$options['mimetype'] = 'text/calendar; charset=utf-8';
 		header('Content-Encoding: identity');
 		header('ETag: '.$this->get_etag($event));
diff --git a/calendar/inc/class.calendar_ical.inc.php b/calendar/inc/class.calendar_ical.inc.php
index 6134bcd1fd..4d1d4a7d82 100644
--- a/calendar/inc/class.calendar_ical.inc.php
+++ b/calendar/inc/class.calendar_ical.inc.php
@@ -109,9 +109,10 @@ class calendar_ical extends calendar_boupdate
 	 * @param string $method='PUBLISH'
 	 * @param boolean $force_own_uid=true ignore the stored and maybe from the client transfered uid and generate a new one
 	 * RalfBecker: GroupDAV/CalDAV requires to switch that non RFC conform behavior off, dont know if SyncML still needs it
+	 * @param boolean $extra_charset_attribute=true GroupDAV/CalDAV dont need the charset attribute and some clients have problems with it
 	 * @return string/boolean string with vCal or false on error (eg. no permission to read the event)
 	 */
-	function &exportVCal($events,$version='1.0', $method='PUBLISH',$force_own_uid=true)
+	function &exportVCal($events,$version='1.0', $method='PUBLISH',$force_own_uid=true,$extra_charset_attribute=true)
 	{
 		$egwSupportedFields = array(
 			'CLASS'			=> array('dbName' => 'public'),
@@ -442,7 +443,7 @@ class calendar_ical extends calendar_boupdate
 					{
 						$options['ENCODING'] = 'QUOTED-PRINTABLE';
 					}
-					if(preg_match('/([\177-\377])/',$valueData))
+					if($extra_charset_attribute && preg_match('/([\177-\377])/',$valueData))
 					{
 						$options['CHARSET'] = 'UTF-8';
 					}