diff --git a/calendar/inc/class.calendar_boupdate.inc.php b/calendar/inc/class.calendar_boupdate.inc.php
index 128263613c..f333de2e1c 100644
--- a/calendar/inc/class.calendar_boupdate.inc.php
+++ b/calendar/inc/class.calendar_boupdate.inc.php
@@ -6,7 +6,7 @@
  * @package calendar
  * @author Ralf Becker <RalfBecker-AT-outdoor-training.de>
  * @author Joerg Lehrke <jlehrke@noc.de>
- * @copyright (c) 2005-12 by RalfBecker-At-outdoor-training.de
+ * @copyright (c) 2005-15 by RalfBecker-At-outdoor-training.de
  * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
  * @version $Id$
  */
@@ -92,11 +92,12 @@ class calendar_boupdate extends calendar_bo
 	 * updates or creates an event, it (optionaly) checks for conflicts and sends the necessary notifications
 	 *
 	 * @param array &$event event-array, on return some values might be changed due to set defaults
-	 * @param boolean $ignore_conflicts=false just ignore conflicts or do a conflict check and return the conflicting events
-	 * @param boolean $touch_modified=true NOT USED ANYMORE (was only used in old csv-import), modified&modifier is always updated!
-	 * @param boolean $ignore_acl=false should we ignore the acl
-	 * @param boolean $updateTS=true update the content history of the event
+	 * @param boolean $ignore_conflicts =false just ignore conflicts or do a conflict check and return the conflicting events
+	 * @param boolean $touch_modified =true NOT USED ANYMORE (was only used in old csv-import), modified&modifier is always updated!
+	 * @param boolean $ignore_acl =false should we ignore the acl
+	 * @param boolean $updateTS =true update the content history of the event
 	 * @param array &$messages=null messages about because of missing ACL removed participants or categories
+	 * @param boolean $skip_notification =false true: send NO notifications, default false = send them
 	 * @return mixed on success: int $cal_id > 0, on error false or array with conflicting events (only if $check_conflicts)
 	 * 		Please note: the events are not garantied to be readable by the user (no read grant or private)!
 	 *
@@ -141,8 +142,7 @@ class calendar_boupdate extends calendar_bo
 			// set owner as participant if none is given
 			if (!is_array($event['participants']) || !count($event['participants']))
 			{
-				$status = $event['owner'] == $this->user ? 'A' : 'U';
-				$status = calendar_so::combine_status($status, 1, 'CHAIR');
+				$status = calendar_so::combine_status($event['owner'] == $this->user ? 'A' : 'U', 1, 'CHAIR');
 				$event['participants'] = array($event['owner'] => $status);
 			}
 		}
@@ -205,6 +205,7 @@ class calendar_boupdate extends calendar_bo
 				{
 					foreach((array)$event['participants'] as $uid => $status)
 					{
+						$q = $r = null;
 						calendar_so::split_status($status,$q,$r);
 						if ($status != 'U')
 						{
@@ -399,7 +400,7 @@ class calendar_boupdate extends calendar_bo
 	 * Remove participants current user has no right to invite
 	 *
 	 * @param array &$event new event
-	 * @param array $old_event=null old event with already invited participants
+	 * @param array $old_event =null old event with already invited participants
 	 * @return array removed participants because of missing invite grants
 	 */
 	public function remove_no_acl_invite(array &$event,array $old_event=null)
@@ -413,7 +414,7 @@ class calendar_boupdate extends calendar_bo
 			$old_event = $this->read($event['id']);
 		}
 		$removed = array();
-		foreach((array)$event['participants'] as $uid => $status)
+		foreach(array_keys((array)$event['participants']) as $uid)
 		{
 			if ((is_null($old_event) || !isset($old_event['participants'][$uid])) && !$this->check_acl_invite($uid))
 			{
@@ -479,7 +480,7 @@ class calendar_boupdate extends calendar_bo
 			}
 		}
 		// Find new participants ...
-		foreach((array)$new_event['participants'] as $new_userid => $new_status)
+		foreach(array_keys((array)$new_event['participants']) as $new_userid)
 		{
 			if(!isset($old_event['participants'][$new_userid]))
 			{
@@ -590,8 +591,8 @@ class calendar_boupdate extends calendar_bo
 	 * Check calendar prefs, if a given user (integer account_id) or email (user or externals) should get notified
 	 *
 	 * @param int|string $user_or_email
-	 * @param string $ical_method='REQUEST'
-	 * @param string $role='REQ-PARTICIPANT'
+	 * @param string $ical_method ='REQUEST'
+	 * @param string $role ='REQ-PARTICIPANT'
 	 * @return boolean true if user requested to be notified, false if not
 	 */
 	static public function email_update_requested($user_or_email, $ical_method='REQUEST', $role='REQ-PARTICIPANT')
@@ -710,8 +711,8 @@ class calendar_boupdate extends calendar_bo
 	 * @param int $msg_type type of the notification: MSG_ADDED, MSG_MODIFIED, MSG_ACCEPTED, ...
 	 * @param array $to_notify numerical user-ids as keys (!) (value is not used)
 	 * @param array $old_event Event before the change
-	 * @param array $new_event=null Event after the change
-	 * @param int $user=0 User who started the notify, default current user
+	 * @param array $new_event =null Event after the change
+	 * @param int $user =0 User who started the notify, default current user
 	 * @return bool true/false
 	 */
 	function send_update($msg_type,$to_notify,$old_event,$new_event=null,$user=0)
@@ -1004,6 +1005,7 @@ class calendar_boupdate extends calendar_bo
 
 	function get_update_message($event,$added)
 	{
+		$nul = null;
 		$details = $this->_get_event_details($event,$added ? lang('Added') : lang('Modified'),$nul);
 
 		$notify_msg = $this->cal_prefs[$added || empty($this->cal_prefs['notifyModified']) ? 'notifyAdded' : 'notifyModified'];
@@ -1051,7 +1053,8 @@ class calendar_boupdate extends calendar_bo
 			$alarm['time'] = $this->date2ts($event['start']) - $alarm['offset'];
 			unset($alarm['times']);
 			unset($alarm['next']);
-			$this->save_alarm($alarm['cal_id'],$alarm);
+			//error_log(__METHOD__."() moving alarm to next recurrence ".array2string($alarm));
+			$this->save_alarm($alarm['cal_id'], $alarm, false);	// false = do NOT update timestamp, as nothing changed for iCal clients
 		}
 		return $ret;
 	}
@@ -1062,8 +1065,8 @@ class calendar_boupdate extends calendar_bo
 	 * This methode converts from user to server time and handles the insertion of users and dates of repeating events
 	 *
 	 * @param array $event
-	 * @param boolean $ignore_acl=false should we ignore the acl
-	 * @param boolean $updateTS=true update the content history of the event
+	 * @param boolean $ignore_acl =false should we ignore the acl
+	 * @param boolean $updateTS =true update the content history of the event
 	 * @return int|boolean $cal_id > 0 or false on error (eg. permission denied)
 	 */
 	function save($event,$ignore_acl=false,$updateTS=true)
@@ -1095,8 +1098,7 @@ class calendar_boupdate extends calendar_bo
 		{
 			if (!empty($event['start']))
 			{
-				$time = new egw_time($event['start'], egw_time::$user_timezone);
-				$time = $this->so->startOfDay($time);
+				$time = $this->so->startOfDay(new egw_time($event['start'], egw_time::$user_timezone));
 				$event['start'] = egw_time::to($time, 'ts');
 				$save_event['start'] = $time;
 			}
@@ -1109,14 +1111,12 @@ class calendar_boupdate extends calendar_bo
 			}
 			if (!empty($event['recurrence']))
 			{
-				$time = new egw_time($event['recurrence'], egw_time::$user_timezone);
-				$time = $this->so->startOfDay($time);
+				$time = $this->so->startOfDay(new egw_time($event['recurrence'], egw_time::$user_timezone));
 				$event['recurrence'] = egw_time::to($time, 'ts');
 			}
 			if (!empty($event['recur_enddate']))
 			{
-				$time = new egw_time($event['recur_enddate'], egw_time::$user_timezone);
-				$time = $this->so->startOfDay($time);
+				$time = $this->so->startOfDay(new egw_time($event['recur_enddate'], egw_time::$user_timezone));
 				$event['recur_enddate'] = egw_time::to($time, 'ts');
 				$time->setUser();
 				$save_event['recur_enddate'] = egw_time::to($time, 'ts');
@@ -1147,8 +1147,7 @@ class calendar_boupdate extends calendar_bo
 			{
 				if ($event['whole_day'])
 				{
-					$time = new egw_time($date, egw_time::$user_timezone);
-					$time =& $this->so->startOfDay($time);
+					$time = $this->so->startOfDay(new egw_time($date, egw_time::$user_timezone));
 					$date = egw_time::to($time, 'ts');
 				}
 				else
@@ -1161,11 +1160,8 @@ class calendar_boupdate extends calendar_bo
 		// same with the alarms
 		if (isset($event['alarm']) && is_array($event['alarm']) && isset($event['start']))
 		{
-			foreach($event['alarm'] as $id => $alarm)
+			foreach($event['alarm'] as $id => &$alarm)
 			{
-				// recalculate alarms to also cope with moved events (beside server time adjustment)
-				$event['alarm'][$id]['time'] = $event['start'] - $alarm['offset'];
-
 				// remove alarms belonging to not longer existing or rejected participants
 				if ($alarm['owner'] && isset($event['participants']))
 				{
@@ -1182,18 +1178,19 @@ class calendar_boupdate extends calendar_bo
 		// update all existing alarm times, in case alarm got moved and alarms are not include in $event
 		if ($old_event && is_array($old_event['alarm']) && isset($event['start']))
 		{
-			foreach($old_event['alarm'] as $id => $alarm)
+			foreach($old_event['alarm'] as $id => &$alarm)
 			{
 				if (!isset($event['alarm'][$id]))
 				{
 					$alarm['time'] = $event['start'] - $alarm['offset'];
-					// remove (not store) alarms belonging to not longer existing or rejected participants
+					if ($alarm['time'] < time()) calendar_so::shift_alarm($event, $alarm);
+						// remove (not store) alarms belonging to not longer existing or rejected participants
 					$status = isset($event['participants']) ? $event['participants'][$alarm['owner']] :
 						$old_event['participants'][$alarm['owner']];
 					if (!$alarm['owner'] || isset($status) && calendar_so::split_status($status) !== 'R')
 					{
-						$this->so->save_alarm($event['id'], $alarm, $this->now);
-						error_log(__LINE__.': '.__METHOD__."() so->save_alarm($event[id], ".array2string($alarm).", $this->now)");
+						$this->so->save_alarm($event['id'], $alarm);
+						error_log(__LINE__.': '.__METHOD__."() so->save_alarm($event[id], ".array2string($alarm).")");
 					}
 					else
 					{
@@ -1229,6 +1226,7 @@ class calendar_boupdate extends calendar_bo
 		{
 			foreach($event['participants'] as $uid => $status)
 			{
+				$user_type = $user_id = null;
 				calendar_so::split_user($uid, $user_type, $user_id);
 				if ($user_type == 'c' && (!$old_event || !isset($old_event['participants'][$uid])))
 				{
@@ -1332,7 +1330,7 @@ class calendar_boupdate extends calendar_bo
 	/**
 	 * Get rights for a given category id
 	 *
-	 * @param int $cat_id=null null to return array with all cats
+	 * @param int $cat_id =null null to return array with all cats
 	 * @return array with account_id => right pairs
 	 */
 	public static function get_cat_rights($cat_id=null)
@@ -1384,7 +1382,7 @@ class calendar_boupdate extends calendar_bo
 	 */
 	public static function has_cat_right($right,$cat_id,$user)
 	{
-		static $cache;
+		static $cache=null;
 
 		if (!isset($cache[$cat_id]))
 		{
@@ -1392,7 +1390,7 @@ class calendar_boupdate extends calendar_bo
 			$cat_rights = self::get_cat_rights($cat_id);
 			if (!is_null($cat_rights))
 			{
-				static $memberships;
+				static $memberships=null;
 				if (is_null($memberships))
 				{
 					$memberships = $GLOBALS['egw']->accounts->memberships($user,true);
@@ -1432,6 +1430,7 @@ class calendar_boupdate extends calendar_bo
 		{
 			return false;
 		}
+		$quantity = $role = null;
 		calendar_so::split_status($status, $quantity, $role);
 		if ($this->log)
 		{
@@ -1486,7 +1485,7 @@ class calendar_boupdate extends calendar_bo
 	 *
 	 * @param array $new_event event-array with the new stati
 	 * @param array $old_event event-array with the old stati
-	 * @param int $recur_date=0 date to change, or 0 = all since now
+	 * @param int $recur_date =0 date to change, or 0 = all since now
 	 * @param boolean $skip_notification Do not send notifications.  Parameter passed on to set_status().
 	 */
 	function update_status($new_event, $old_event , $recur_date=0, $skip_notification=false)
@@ -1517,10 +1516,10 @@ class calendar_boupdate extends calendar_bo
 	 * deletes an event
 	 *
 	 * @param int $cal_id id of the event to delete
-	 * @param int $recur_date=0 if a single event from a series should be deleted, its date
-	 * @param boolean $ignore_acl=false true for no ACL check, default do ACL check
-	 * @param boolean $skip_notification=false
-	 * @param boolean $delete_exceptions=true true: delete, false: keep exceptions (with new UID)
+	 * @param int $recur_date =0 if a single event from a series should be deleted, its date
+	 * @param boolean $ignore_acl =false true for no ACL check, default do ACL check
+	 * @param boolean $skip_notification =false
+	 * @param boolean $delete_exceptions =true true: delete, false: keep exceptions (with new UID)
 	 * @param int &$exceptions_kept=null on return number of kept exceptions
 	 * @return boolean true on success, false on error (usually permission denied)
 	 */
@@ -1594,6 +1593,7 @@ class calendar_boupdate extends calendar_bo
 			// check if deleted recurrance has alarms (because it's the next recurrance) --> move it to next recurrance
 			if ($event['alarm'])
 			{
+				$next_recurrance = null;
 				foreach($event['alarm'] as &$alarm)
 				{
 					if (($alarm['time'] == $recur_date) || ($alarm['time']+$alarm['offset'] == $recur_date))
@@ -1604,19 +1604,10 @@ class calendar_boupdate extends calendar_bo
 						{
 							$checkdate = $recur_date;
 							//if ($alarm['time']+$alarm['offset'] == $recur_date) $checkdate = $recur_date + $alarm['offset'];
-							if ($e = $this->read($cal_id,$checkdate+1))
+							if (($e = $this->read($cal_id,$checkdate+1)))
 							{
 								$next_recurrance = $this->date2ts($e['start']);
 							}
-							/*
-							foreach(calendar_rrule::event2rrule($event, true) as $time)
-							{
-								$time->setUser();	// $time is in timezone of event, convert it to usertime used here
-								$next_recurrance = $this->date2ts($time);
-								if ($next_recurrance > $checkdate) break;
-							}
-							*/
-							//error_log(__METHOD__.__LINE__." $next_recurrance > $checkdate");
 						}
 						$alarm['time'] = $this->date2ts($next_recurrance, true);	// user to server-time
 						$alarm['cal_id'] = $cal_id;
@@ -1644,6 +1635,11 @@ class calendar_boupdate extends calendar_bo
 	/**
 	 * helper for send_update and get_update_message
 	 * @internal
+	 * @param array $event
+	 * @param string $action
+	 * @param array $event_arr
+	 * @param array $disinvited
+	 * @return array
 	 */
 	function _get_event_details($event,$action,&$event_arr,$disinvited=array())
 	{
@@ -1787,8 +1783,8 @@ class calendar_boupdate extends calendar_bo
 	 *
 	 * @param array $event2save event-data before calling save
 	 * @param array $event_saved event-data read back from the DB
-	 * @param array $old_event=null event-data in the DB before calling save
-	 * @param string $type='update'
+	 * @param array $old_event =null event-data in the DB before calling save
+	 * @param string $type ='update'
 	 */
 	function log2file($event2save,$event_saved,$old_event=null,$type='update')
 	{
@@ -1820,9 +1816,10 @@ class calendar_boupdate extends calendar_bo
 	 *
 	 * @param int $cal_id Id of the calendar-entry
 	 * @param array $alarm array with fields: text, owner, enabled, ..
+	 * @param boolean $update_modified =true call update modified, default true
 	 * @return string id of the alarm, or false on error (eg. no perms)
 	 */
-	function save_alarm($cal_id,$alarm)
+	function save_alarm($cal_id, $alarm, $update_modified=true)
 	{
 		if (!$cal_id || !$this->check_perms(EGW_ACL_EDIT,$alarm['all'] ? $cal_id : 0,!$alarm['all'] ? $alarm['owner'] : 0))
 		{
@@ -1833,7 +1830,7 @@ class calendar_boupdate extends calendar_bo
 
 		$GLOBALS['egw']->contenthistory->updateTimeStamp('calendar', $cal_id, 'modify', $this->now);
 
-		return $this->so->save_alarm($cal_id,$alarm);
+		return $this->so->save_alarm($cal_id, $alarm, $update_modified);
 	}
 
 	/**
@@ -1861,7 +1858,7 @@ class calendar_boupdate extends calendar_bo
 	 * currently used for ical/sif import
 	 *
 	 * @param array $catname_list names of the categories which should be found or added
-	 * @param int|array $old_event=null match against existing event and expand the returned category ids
+	 * @param int|array $old_event =null match against existing event and expand the returned category ids
 	 *  by the ones the user normally does not see due to category permissions - used to preserve categories
 	 * @return array category ids (found, added and preserved categories)
 	 */
@@ -2191,7 +2188,7 @@ class calendar_boupdate extends calendar_bo
 				if ($filter == 'master')
 				{
 					// We found the master
-					$matchingEvents = array($egwEvent['id']);;
+					$matchingEvents = array($egwEvent['id']);
 					break;
 				}
 				if ($filter == 'exact')
@@ -2446,14 +2443,14 @@ class calendar_boupdate extends calendar_bo
 		}
 
 		// append pseudos as last entries
-		$matchingEvents = array_merge($matchingEvents, $pseudos);
+		$matches = array_merge($matchingEvents, $pseudos);
 
 		if ($this->log)
 		{
 			error_log(__FILE__.'['.__LINE__.'] '.__METHOD__.
-				'[MATCHES]:' . array2string($matchingEvents)."\n",3,$this->logfile);
+				'[MATCHES]:' . array2string($matches)."\n",3,$this->logfile);
 		}
-		return $matchingEvents;
+		return $matches;
 	}
 
 	/**
@@ -2493,8 +2490,8 @@ class calendar_boupdate extends calendar_bo
 			{
 				$type = 'SERIES-PSEUDO-EXCEPTION';
 				$wasPseudo = true;
-				list($eventID, $recur_date) = explode(':', $eventID);
-				$recur_date = $this->date2usertime($recur_date);
+				list($eventID, $date) = explode(':', $eventID);
+				$recur_date = $this->date2usertime($date);
 				$stored_event = $this->read($eventID, $recur_date, false, 'server');
 				$master_event = $this->read($eventID, 0, false, 'server');
 				$recurrence_event = $stored_event;
diff --git a/calendar/inc/class.calendar_groupdav.inc.php b/calendar/inc/class.calendar_groupdav.inc.php
index cc27acfb67..7c7959c831 100644
--- a/calendar/inc/class.calendar_groupdav.inc.php
+++ b/calendar/inc/class.calendar_groupdav.inc.php
@@ -7,7 +7,7 @@
  * @package calendar
  * @subpackage groupdav
  * @author Ralf Becker <RalfBecker-AT-outdoor-training.de>
- * @copyright (c) 2007-13 by Ralf Becker <RalfBecker-AT-outdoor-training.de>
+ * @copyright (c) 2007-15 by Ralf Becker <RalfBecker-AT-outdoor-training.de>
  * @version $Id$
  */
 
@@ -135,7 +135,7 @@ class calendar_groupdav extends groupdav_handler
 	 * @param array &$options
 	 * @param array &$files
 	 * @param int $user account_id
-	 * @param string $id=''
+	 * @param string $id =''
 	 * @return mixed boolean true on success, false on failure or string with http status (eg. '404 Not Found')
 	 */
 	function propfind($path,&$options,&$files,$user,$id='')
@@ -157,6 +157,7 @@ class calendar_groupdav extends groupdav_handler
 			'daywise' => false,
 			'date_format' => 'server',
 			'no_total' => true,	// we need no total number of rows (saves extra query)
+			'cfs' => array(),	// return custom-fields, as we use them to store X- attributes
 		);
 		foreach(array(
 			'start' => $GLOBALS['egw_info']['user']['preferences']['groupdav']['calendar-past-limit'],
@@ -252,7 +253,7 @@ class calendar_groupdav extends groupdav_handler
 	 *
 	 * @param string $path
 	 * @param array $filter
-	 * @param array|boolean $start=false false=return all or array(start,num)
+	 * @param array|boolean $start =false false=return all or array(start,num)
 	 * @return array with "files" array with values for keys path and props
 	 */
 	function propfind_callback($path,array $filter,$start=false)
@@ -289,6 +290,7 @@ class calendar_groupdav extends groupdav_handler
 					$files[] = array('path' => $path.urldecode($this->get_path($event)));
 					continue;
 				}
+				$schedule_tag = null;
 				$etag = $this->get_etag($event, $schedule_tag);
 
 				//header('X-EGROUPWARE-EVENT-'.$event['id'].': '.$event['title'].': '.date('Y-m-d H:i:s',$event['start']).' - '.date('Y-m-d H:i:s',$event['end']));
@@ -555,7 +557,7 @@ class calendar_groupdav extends groupdav_handler
 	 *
 	 * @param array &$options
 	 * @param int $id
-	 * @param int $user=null account_id
+	 * @param int $user =null account_id
 	 * @return mixed boolean true on success, false on failure or string with http status (eg. '404 Not Found')
 	 */
 	function get(&$options,$id,$user=null)
@@ -568,6 +570,7 @@ class calendar_groupdav extends groupdav_handler
 		$options['data'] = $this->iCal($event, $user, strpos($options['path'], '/inbox/') !== false ? 'REQUEST' : null);
 		$options['mimetype'] = 'text/calendar; charset=utf-8';
 		header('Content-Encoding: identity');
+		$schedule_tag = null;
 		header('ETag: "'.$this->get_etag($event, $schedule_tag).'"');
 		if ($this->use_schedule_tag)
 		{
@@ -582,9 +585,9 @@ class calendar_groupdav extends groupdav_handler
 	 * Taking into account virtual an real exceptions for recuring events
 	 *
 	 * @param array $event
-	 * @param int $user=null account_id of calendar to display
-	 * @param string $method=null eg. 'PUBLISH' for inbox, nothing anywhere else
-	 * @param boolean|array $expand=false true or array with values for 'start', 'end' to expand recurrences
+	 * @param int $user =null account_id of calendar to display
+	 * @param string $method =null eg. 'PUBLISH' for inbox, nothing anywhere else
+	 * @param boolean|array $expand =false true or array with values for 'start', 'end' to expand recurrences
 	 * @return string
 	 */
 	private function iCal(array $event,$user=null, $method=null, $expand=false)
@@ -626,9 +629,9 @@ class calendar_groupdav extends groupdav_handler
 	 * Maybe that should be part of calendar_bo
 	 *
 	 * @param string $uid UID
-	 * @param calendar_bo $bo=null calendar_bo object to reuse for search call
-	 * @param boolean|array $expand=false true or array with values for 'start', 'end' to expand recurrences
-	 * @param int $user=null account_id of calendar to display, to remove master, if current user does not participate in
+	 * @param calendar_bo $bo =null calendar_bo object to reuse for search call
+	 * @param boolean|array $expand =false true or array with values for 'start', 'end' to expand recurrences
+	 * @param int $user =null account_id of calendar to display, to remove master, if current user does not participate in
 	 * @return array
 	 */
 	private static function &get_series($uid,calendar_bo $bo=null, $expand=false, $user=null)
@@ -640,6 +643,7 @@ class calendar_groupdav extends groupdav_handler
 			'filter' => 'owner',  // return all possible entries
 			'daywise' => false,
 			'date_format' => 'server',
+			'cfs' => array(),	// read cfs as we use them to store X- attributes
 		);
 		if (is_array($expand)) $params += $expand;
 
@@ -690,6 +694,13 @@ class calendar_groupdav extends groupdav_handler
 				}
 				continue;	// nothing to change
 			}
+			// alarms are reported on recurrences --> move them to master
+			foreach($recurrence['alarm'] as $alarm)
+			{
+				$master['alarm'][] = $alarm;
+			}
+			$recurrence['alarm'] = array();
+
 			// now we need to check if this recurrence is an exception
 			if (!$expand && $master['participants'] == $recurrence['participants'])
 			{
@@ -731,8 +742,8 @@ class calendar_groupdav extends groupdav_handler
 	 *
 	 * @param array &$options
 	 * @param int $id
-	 * @param int $user=null account_id of owner, default null
-	 * @param string $prefix=null user prefix from path (eg. /ralf from /ralf/addressbook)
+	 * @param int $user =null account_id of owner, default null
+	 * @param string $prefix =null user prefix from path (eg. /ralf from /ralf/addressbook)
 	 * @return mixed boolean true on success, false on failure or string with http status (eg. '404 Not Found')
 	 */
 	function put(&$options,$id,$user=null,$prefix=null)
@@ -811,6 +822,7 @@ class calendar_groupdav extends groupdav_handler
 			{
 				$schedule_tag_match = $_SERVER['HTTP_IF_SCHEDULE_TAG_MATCH'];
 				if ($schedule_tag_match[0] == '"') $schedule_tag_match = substr($schedule_tag_match, 1, -1);
+				$schedule_tag = null;
 				$this->get_etag($oldEvent, $schedule_tag);
 
 				if ($schedule_tag_match !== $schedule_tag)
@@ -835,6 +847,7 @@ class calendar_groupdav extends groupdav_handler
 				if (($events = $handler->icaltoegw($vCalendar)))
 				{
 					$modified = 0;
+					$series = null;
 					foreach($events as $n => $event)
 					{
 						// for recurrances of event series, we need to read correct recurrence (or if series master is no first event)
@@ -883,7 +896,8 @@ class calendar_groupdav extends groupdav_handler
 						// import alarms, if given and changed
 						if ((array)$event['alarm'] !== (array)$oldEvent['alarm'])
 						{
-							$modified += $this->sync_alarms($oldEvent['id'], (array)$event['alarm'], (array)$oldEvent['alarm'], $user, $event['start']);
+							$event['id'] = $oldEvent['id'];
+							$modified += $handler->sync_alarms($event, (array)$oldEvent['alarm'], $user);
 						}
 					}
 					if (!$modified)	// NO modififictions, or none we understood --> log it and return Ok: "204 No Content"
@@ -951,59 +965,12 @@ class calendar_groupdav extends groupdav_handler
 		return $retval;
 	}
 
-	/**
-	 * Sync alarms of current user: add alarms added on client and remove the ones removed
-	 *
-	 * @param int $cal_id of event to set alarms
-	 * @param array $alarms
-	 * @param array $old_alarms
-	 * @param int $user account_id of user to create alarm for
-	 * @param int $start start-time of event
-	 * @ToDo store other alarm properties like: ACTION, DESCRIPTION, X-WR-ALARMUID
-	 * @return int number of modified alarms
-	 */
-	private function sync_alarms($cal_id, array $alarms, array $old_alarms, $user, $start)
-	{
-		if ($this->debug) error_log(__METHOD__."($cal_id, ".array2string($alarms).', '.array2string($old_alarms).", $user, $start)");
-		$modified = 0;
-		foreach($alarms as $alarm)
-		{
-			if ($alarm['owner'] != $this->user) continue;	// only import alarms of current user
-
-			// check if alarm is already stored or from other users
-			foreach($old_alarms as $id => $old_alarm)
-			{
-				if ($old_alarm['owner'] != $user || $alarm['offset'] == $old_alarm['offset'])
-				{
-					unset($old_alarms[$id]);	// remove alarms of other user, or already existing alarms
-				}
-			}
-			// alarm not found --> add it
-			if ($alarm['offset'] != $old_alarm['offset'] || $old_alarm['owner'] != $user)
-			{
-				$alarm['owner'] = $user;
-				$alarm['time'] = $start - $alarm['offset'];
-				if ($this->debug) error_log(__METHOD__."() adding new alarm from client ".array2string($alarm));
-				$this->bo->save_alarm($cal_id, $alarm);
-				++$modified;
-			}
-		}
-		// remove all old alarms left from current user
-		foreach($old_alarms as $id => $old_alarm)
-		{
-			if ($this->debug) error_log(__METHOD__."() deleting alarm '$id' deleted on client ".array2string($old_alarm));
-			$this->bo->delete_alarm($id);
-			++$modified;
-		}
-		return $modified;
-	}
-
 	/**
 	 * Handle post request for a schedule entry
 	 *
 	 * @param array &$options
 	 * @param int $id
-	 * @param int $user=null account_id of owner, default null
+	 * @param int $user =null account_id of owner, default null
 	 * @return mixed boolean true on success, false on failure or string with http status (eg. '404 Not Found')
 	 */
 	function post(&$options,$id,$user=null)
@@ -1057,8 +1024,8 @@ class calendar_groupdav extends groupdav_handler
 			$handler = $this->_get_handler();
 			if (($foundEvents = $handler->search($vCalendar, null, false, $charset)))
 			{
-				$eventId = array_shift($foundEvents);
-				list($eventId) = explode(':', $eventId);
+				$id = array_shift($foundEvents);
+				list($eventId) = explode(':', $id);
 
 				if (!($cal_id = $handler->importVCal($vCalendar, $eventId, null,
 					false, 0, $this->groupdav->current_user_principal, $user, $charset)))
@@ -1082,6 +1049,8 @@ class calendar_groupdav extends groupdav_handler
 	 */
 	protected function outbox_freebusy_request($ical, $charset, $user, array &$options)
 	{
+		unset($options);	// not used, but required by function signature
+
 		$vcal = new Horde_Icalendar();
 		if (!$vcal->parsevCalendar($ical, 'VCALENDAR', $charset))
 		{
@@ -1108,7 +1077,7 @@ class calendar_groupdav extends groupdav_handler
 		$organizer = $component->getAttribute('ORGANIZER');
 		$attendees = (array)$component->getAttribute('ATTENDEE');
 		// X-CALENDARSERVER-MASK-UID specifies to exclude given event from busy-time
-		$mask_uid = $component->getAttribute('X-CALENDARSERVER-MASK-UID');
+		$mask_uid = $component->getAttributeDefault('X-CALENDARSERVER-MASK-UID', null);
 
 		header('Content-type: text/xml; charset=UTF-8');
 
@@ -1118,7 +1087,7 @@ class calendar_groupdav extends groupdav_handler
 		$xml->startDocument('1.0', 'UTF-8');
 		$xml->startElementNs('C', 'schedule-response', groupdav::CALDAV);
 
-		foreach($event['participants'] as $uid => $status)
+		foreach(array_keys($event['participants']) as $uid)
 		{
 			$xml->startElementNs('C', 'response', null);
 
@@ -1155,6 +1124,7 @@ class calendar_groupdav extends groupdav_handler
 	 */
 	function free_busy_report($path,$options,$user)
 	{
+		unset($path);	// unused, but required by function signature
 		if (!$this->bo->check_perms(EGW_ACL_FREEBUSY, 0, $user))
 		{
 			return '403 Forbidden';
@@ -1180,7 +1150,7 @@ class calendar_groupdav extends groupdav_handler
 	 * Reimplemented to add read-free-busy and schedule-deliver privilege
 	 *
 	 * @param string $path path of collection
-	 * @param int $user=null owner of the collection, default current user
+	 * @param int $user =null owner of the collection, default current user
 	 * @return array with privileges
 	 */
 	public function current_user_privileges($path, $user=null)
@@ -1306,7 +1276,7 @@ class calendar_groupdav extends groupdav_handler
 				// check if user is a participant or one of the groups he is a member of --> reject the meeting request
 				$ret = '403 Forbidden';
 				$memberships = $GLOBALS['egw']->accounts->memberships($this->bo->user, true);
-				foreach($event['participants'] as $uid => $status)
+				foreach(array_keys($event['participants']) as $uid)
 				{
 					if ($this->bo->user == $uid || in_array($uid, $memberships))
 					{
@@ -1391,7 +1361,8 @@ class calendar_groupdav extends groupdav_handler
 	/**
 	 * Get the etag for an entry
 	 *
-	 * @param array|int $event array with event or cal_id
+	 * @param array|int $entry array with event or cal_id
+	 * @param string $schedule_tag =null on return schedule-tag
 	 * @return string|boolean string with etag or false
 	 */
 	function get_etag($entry, &$schedule_tag=null)
@@ -1410,10 +1381,11 @@ class calendar_groupdav extends groupdav_handler
 	 * @param int|array $entry id or array of new created entry
 	 * @param string $path
 	 * @param int|string $retval
-	 * @param boolean $path_attr_is_name=true true: path_attr is ca(l|rd)dav_name, false: id (GroupDAV needs Location header)
+	 * @param boolean $path_attr_is_name =true true: path_attr is ca(l|rd)dav_name, false: id (GroupDAV needs Location header)
 	 */
 	function put_response_headers($entry, $path, $retval, $path_attr_is_name=true)
 	{
+		$schedule_tag = null;
 		$etag = $this->get_etag($entry, $schedule_tag);
 
 		if ($this->use_schedule_tag)
@@ -1443,15 +1415,16 @@ class calendar_groupdav extends groupdav_handler
 	/**
 	 * Add extra properties for calendar collections
 	 *
-	 * @param array $props=array() regular props by the groupdav handler
+	 * @param array $props regular props by the groupdav handler
 	 * @param string $displayname
-	 * @param string $base_uri=null base url of handler
-	 * @param int $user=null account_id of owner of current collection
-	 * @param string $path=null path of the collection
+	 * @param string $base_uri =null base url of handler
+	 * @param int $user =null account_id of owner of current collection
+	 * @param string $path =null path of the collection
 	 * @return array
 	 */
-	public function extra_properties(array $props=array(), $displayname, $base_uri=null, $user=null, $path=null)
+	public function extra_properties(array $props, $displayname, $base_uri=null, $user=null, $path=null)
 	{
+		unset($base_uri);	// unused, but required by function signature
 		if (!isset($props['calendar-description']))
 		{
 			// default calendar description: can be overwritten via PROPPATCH, in which case it's already set
@@ -1523,8 +1496,8 @@ class calendar_groupdav extends groupdav_handler
 	function get_shared()
 	{
 		$shared = array();
-		$calendar_home_set = $GLOBALS['egw_info']['user']['preferences']['groupdav']['calendar-home-set'];
-		$calendar_home_set = $calendar_home_set ? explode(',',$calendar_home_set) : array();
+		$pref = $GLOBALS['egw_info']['user']['preferences']['groupdav']['calendar-home-set'];
+		$calendar_home_set = $pref ? explode(',', $pref) : array();
 		// replace symbolic id's with real nummeric id's
 		foreach(array(
 			'G' => $GLOBALS['egw_info']['user']['account_primary_group'],
diff --git a/calendar/inc/class.calendar_ical.inc.php b/calendar/inc/class.calendar_ical.inc.php
index b9d436999d..2fffd50379 100644
--- a/calendar/inc/class.calendar_ical.inc.php
+++ b/calendar/inc/class.calendar_ical.inc.php
@@ -251,9 +251,9 @@ class calendar_ical extends calendar_boupdate
 			{
 				if ($this->read($event, $recurrence, true, 'server'))
 				{
-					if ($this->bo->check_perms(EGW_ACL_FREEBUSY, $event, 0, 'server'))
+					if ($this->check_perms(EGW_ACL_FREEBUSY, $event, 0, 'server'))
 					{
-						$this->bo->clear_private_infos($event, array($this->user, $event['owner']));
+						$this->clear_private_infos($event, array($this->user, $event['owner']));
 					}
 					else
 					{
@@ -631,7 +631,10 @@ class calendar_ical extends calendar_boupdate
 						else // $version == '2.0'
 						{
 							$attributes['RRULE'] = '';
-							$parameters['RRULE'] = $rrule;
+							foreach($rrule as $n => $v)
+							{
+								$attributes['RRULE'] .= ($attributes['RRULE']?';':'').$n.'='.$v;
+							}
 						}
 						break;
 
@@ -833,6 +836,25 @@ class calendar_ical extends calendar_boupdate
 				}
 			}
 
+			// for CalDAV add all X-Properties previously parsed
+			if ($this->productManufacturer == 'groupdav' || $this->productManufacturer == 'file')
+			{
+				foreach($event as $name => $value)
+				{
+					if (substr($name, 0, 2) == '##')
+					{
+						if (($attr = json_decode($value, true)) && is_array($attr))
+						{
+							$vevent->setAttribute(substr($name, 2), $attr['value'], $attr['params'], true, $attr['values']);
+						}
+						else
+						{
+							$vevent->setAttribute(substr($name, 2), $value);
+						}
+					}
+				}
+			}
+
 			if ($this->productManufacturer == 'nokia')
 			{
 				if ($event['special'] == '1')
@@ -862,7 +884,7 @@ class calendar_ical extends calendar_boupdate
 			foreach ((array)$event['alarm'] as $alarmData)
 			{
 				// skip over alarms that don't have the minimum required info
-				if (!$alarmData['offset'] && !$alarmData['time']) continue;
+				if (!isset($alarmData['offset']) && !isset($alarmData['time'])) continue;
 
 				// skip alarms not being set for all users and alarms owned by other users
 				if ($alarmData['all'] != true && $alarmData['owner'] != $this->user)
@@ -899,8 +921,9 @@ class calendar_ical extends calendar_boupdate
 					// VCalendar 2.0 / RFC 2445
 
 					// RFC requires DESCRIPTION for DISPLAY
-					if (!$event['title'] && !$description) continue;
+					if (!$event['title'] && !$description) $description = 'Alarm';
 
+					/* Disabling for now
 					// Lightning infinitly pops up alarms for recuring events, if the only use an offset
 					if ($this->productName == 'lightning' && $event['recur_type'] != MCAL_RECUR_NONE)
 					{
@@ -914,7 +937,7 @@ class calendar_ical extends calendar_boupdate
 						{
 							continue;
 						}
-					}
+					}*/
 
 					// for SyncML non-whole-day events always use absolute times
 					// (probably because some devices have no clue about timezones)
@@ -930,7 +953,7 @@ class calendar_ical extends calendar_boupdate
 					if ($alarmData['offset'] !== false)
 					{
 						$valarm->setAttribute('TRIGGER', -$alarmData['offset'],
-								array('VALUE' => 'DURATION', 'RELATED' => 'START'));
+							array('VALUE' => 'DURATION', 'RELATED' => 'START'));
 					}
 					else
 					{
@@ -938,9 +961,28 @@ class calendar_ical extends calendar_boupdate
 						$value = self::getDateTime($alarmData['time'],$tzid,$params);
 						$valarm->setAttribute('TRIGGER', $value, $params);
 					}
-
-					$valarm->setAttribute('ACTION','DISPLAY');
-					$valarm->setAttribute('DESCRIPTION',$event['title'] ? $event['title'] : $description);
+					if (!empty($alarmData['uid']))
+					{
+						$valarm->setAttribute('UID', $alarmData['uid']);
+						$valarm->setAttribute('X-WR-ALARMUID', $alarmData['uid']);
+					}
+					// set evtl. existing attributes set by iCal clients not used by EGroupware
+					if (isset($alarmData['attrs']))
+					{
+						foreach($alarmData['attrs'] as $attr => $data)
+						{
+							$valarm->setAttribute($attr, $data['value'], $data['params']);
+						}
+					}
+					// set default ACTION and DESCRIPTION, if not set by a client
+					if (!isset($alarmData['attrs']) || !isset($alarmData['attrs']['ACTION']))
+					{
+						$valarm->setAttribute('ACTION','DISPLAY');
+					}
+					if (!isset($alarmData['attrs']) || !isset($alarmData['attrs']['DESCRIPTION']))
+					{
+						$valarm->setAttribute('DESCRIPTION',$event['title'] ? $event['title'] : $description);
+					}
 					$vevent->addComponent($valarm);
 				}
 			}
@@ -968,6 +1010,7 @@ class calendar_ical extends calendar_boupdate
 								{
 									$paramData['ENCODING'] = 'QUOTED-PRINTABLE';
 								}
+								/* disable automatic QP encoding eg. for new-lines as it also encodes non-ascii/utf-8 which TB does NOT decode
 								else
 								{
 									$paramData['CHARSET'] = '';
@@ -979,7 +1022,7 @@ class calendar_ical extends calendar_boupdate
 									{
 										$paramData['ENCODING'] = '';
 									}
-								}
+								}*/
 								break;
 							case 'funambol':
 								$paramData['ENCODING'] = 'FUNAMBOL-QP';
@@ -1216,6 +1259,14 @@ class calendar_ical extends calendar_boupdate
 						}
 					}
 				}
+				// unset old X-* attributes stored in custom-fields
+				foreach ($event_info['stored_event'] as $key => $value)
+				{
+					if ($key[0] == '#' && $key[1] == '#' && !isset($event[$key]))
+					{
+						$event[$key] = '';
+					}
+				}
 				if ($merge)
 				{
 					if ($this->log)
@@ -1422,46 +1473,9 @@ class calendar_ical extends calendar_boupdate
 					case 'SERIES-MASTER':
 					case 'SERIES-EXCEPTION':
 					case 'SERIES-EXCEPTION-PROPAGATE':
-						if (count($event['alarm']) > 0)
+						if (isset($event['alarm']))
 						{
-							foreach ($event['alarm'] as $newid => &$alarm)
-							{
-								if (!isset($alarm['offset']) && isset($alarm['time']))
-								{
-									$alarm['offset'] = $event['start'] - $alarm['time'];
-								}
-								elseif (!isset($alarm['time']) && isset($alarm['offset']))
-								{
-									$alarm['time'] = $event['start'] - $alarm['offset'];
-								}
-								$alarm['owner'] = $this->user;
-								$alarm['all'] = false;
-
-								// if no edit rights, allow participants to set alarms directly (like status)
-								if ($event_info['stored_event'] && !$event_info['acl_edit'])
-								{
-									if ($alarm['time'] < time() && !calendar_so::shift_alarm($event, $alarm))
-									{
-										continue;	//pgoerzen: don't add an alarm in the past
-									}
-									$this->save_alarm($event_info['stored_event']['id'], $alarm);
-								}
-
-								if (is_array($event_info['stored_event'])
-										&& count($event_info['stored_event']['alarm']) > 0)
-								{
-									foreach ($event_info['stored_event']['alarm'] as $alarm_id => $alarm_data)
-									{
-										if ($alarm['offset'] == $alarm_data['offset'] &&
-											($alarm_data['all'] || $alarm_data['owner'] == $this->user))
-										{
-											unset($event['alarm'][$newid]);
-											unset($event_info['stored_event']['alarm'][$alarm_id]);
-											continue 2;
-										}
-									}
-								}
-							}
+							$this->sync_alarms($event, (array)$event_info['stored_event']['alarm'], $this->user);
 						}
 						break;
 
@@ -1469,18 +1483,6 @@ class calendar_ical extends calendar_boupdate
 						// nothing to do here
 						break;
 				}
-				if (is_array($event_info['stored_event'])
-						&& count($event_info['stored_event']['alarm']) > 0)
-				{
-					foreach ($event_info['stored_event']['alarm'] as $alarm_id => $alarm_data)
-					{
-						// only touch own alarms
-						if ($alarm_data['all'] == false && $alarm_data['owner'] == $this->user)
-						{
-							$this->delete_alarm($alarm_id);
-						}
-					}
-				}
 			}
 
 			if ($this->log)
@@ -1764,6 +1766,73 @@ class calendar_ical extends calendar_boupdate
 		return $updated_id === 0 ? 0 : $return_id;
 	}
 
+	/**
+	 * Sync alarms of current user: add alarms added on client and remove the ones removed
+	 *
+	 * @param array& $event
+	 * @param array $old_alarms
+	 * @param int $user account_id of user to create alarm for
+	 * @return int number of modified alarms
+	 */
+	public function sync_alarms(array &$event, array $old_alarms, $user)
+	{
+		if ($this->debug) error_log(__METHOD__."(".array2string($event).', old_alarms='.array2string($old_alarms).", $user,)");
+		$modified = 0;
+		foreach($event['alarm'] as &$alarm)
+		{
+			// check if alarm is already stored or from other users
+			foreach($old_alarms as $id => $old_alarm)
+			{
+				// not current users alarm --> ignore
+				if (!$old_alarm['all'] && $old_alarm['owner'] != $user)
+				{
+					unset($old_alarm[$id]);
+					continue;
+				}
+				// alarm found --> stop
+				if (empty($alarm['uid']) && $alarm['offset'] == $old_alarm['offset'] || $alarm['uid'] && $alarm['uid'] == $old_alarm['uid'])
+				{
+					unset($old_alarms[$id]);
+					break;
+				}
+			}
+			// alarm not found --> add it
+			if ($alarm['offset'] != $old_alarm['offset'] || $old_alarm['owner'] != $user && !$alarm['all'])
+			{
+				$alarm['owner'] = $user;
+				if (!isset($alarm['time'])) $alarm['time'] = $event['start'] - $alarm['offset'];
+				if ($alarm['time'] < time()) calendar_so::shift_alarm($event, $alarm);
+				if ($this->debug) error_log(__METHOD__."() adding new alarm from client ".array2string($alarm));
+				if ($event['id']) $alarm['id'] = $this->save_alarm($event['id'], $alarm);
+				++$modified;
+			}
+			// existing alarm --> update it
+			elseif ($alarm['offset'] == $old_alarm['offset'] && ($old_alarm['owner'] == $user || $old_alarm['all']))
+			{
+				if (!isset($alarm['time'])) $alarm['time'] = $event['start'] - $alarm['offset'];
+				if ($alarm['time'] < time()) calendar_so::shift_alarm($event, $alarm);
+				$alarm = array_merge($old_alarm, $alarm);
+				if ($this->debug) error_log(__METHOD__."() updating existing alarm from client ".array2string($alarm));
+				$alarm['id'] = $this->save_alarm($event['id'], $alarm);
+				++$modified;
+			}
+		}
+		// remove all old alarms left from current user
+		foreach($old_alarms as $id => $old_alarm)
+		{
+			// not current users alarm --> ignore
+			if (!$old_alarm['all'] && $old_alarm['owner'] != $user)
+			{
+				unset($old_alarm[$id]);
+				continue;
+			}
+			if ($this->debug) error_log(__METHOD__."() deleting alarm '$id' deleted on client ".array2string($old_alarm));
+			$this->delete_alarm($id);
+			++$modified;
+		}
+		return $modified;
+	}
+
 	/**
 	 * get the value of an attribute by its name
 	 *
@@ -1784,9 +1853,17 @@ class calendar_ical extends calendar_boupdate
 		return false;
 	}
 
-	static function valarm2egw(&$alarms, &$valarm)
+	/**
+	 * Parsing a valarm component preserving all attributes unknown to EGw
+	 *
+	 * @param array &$alarms on return alarms parsed
+	 * @param Horde_Icalendar_Valarm $valarm valarm component
+	 * @param int $duration in seconds to be able to convert RELATED=END
+	 * @return int number of parsed alarms
+	 */
+	static function valarm2egw(&$alarms, Horde_Icalendar_Valarm $valarm, $duration)
 	{
-		$count = 0;
+		$alarm = array();
 		foreach ($valarm->getAllAttributes() as $vattr)
 		{
 			switch ($vattr['name'])
@@ -1797,40 +1874,47 @@ class calendar_ical extends calendar_boupdate
 					switch ($vtype)
 					{
 						case 'DURATION':
-							if (isset($vattr['params']['RELATED'])
-								&& $vattr['params']['RELATED'] != 'START')
+							if (isset($vattr['params']['RELATED']) && $vattr['params']['RELATED'] == 'END')
+							{
+								$alarm['offset'] = $duration -$vattr['value'];
+							}
+							elseif (isset($vattr['params']['RELATED']) && $vattr['params']['RELATED'] != 'START')
 							{
 								error_log("Unsupported VALARM offset anchor ".$vattr['params']['RELATED']);
+								return;
 							}
 							else
 							{
-								$alarms[] = array('offset' => -$vattr['value']);
-								$count++;
+								$alarm['offset'] = -$vattr['value'];
 							}
 							break;
 						case 'DATE-TIME':
-							$alarms[] = array('time' => $vattr['value']);
-							$count++;
+							$alarm['time'] = $vattr['value'];
 							break;
 						default:
-							// we should also do ;RELATED=START|END
 							error_log('VALARM/TRIGGER: unsupported value type:' . $vtype);
 					}
 					break;
-				case 'ACTION':
-				case 'DISPLAY':
-				case 'DESCRIPTION':
-				case 'SUMMARY':
-				case 'ATTACH':
-				case 'ATTENDEE':
-					// we ignore these fields silently
-				 	break;
 
-				default:
-					error_log('VALARM field ' .$vattr['name'] . ': ' . $vattr['value'] . ' HAS NO CONVERSION YET');
+				case 'UID':
+				case 'X-WR-ALARMUID':
+					$alarm['uid'] = $vattr['value'];
+					break;
+
+				default:	// store all other attributes, so we dont loose them
+					$alarm['attrs'][$vattr['name']] = array(
+						'params' => $vattr['params'],
+						'value'  => $vattr['value'],
+					);
 			}
 		}
-		return $count;
+		if (isset($alarm['offset']) || isset($alarm['time']))
+		{
+			//error_log(__METHOD__."(..., ".$valarm->exportvCalendar().", $duration) alarm=".array2string($alarm));
+			$alarms[] = $alarm;
+			return 1;
+		}
+		return 0;
 	}
 
 	function setSupportedFields($_productManufacturer='', $_productName='')
@@ -2246,7 +2330,7 @@ class calendar_ical extends calendar_boupdate
 		{
 			if (is_a($valarm, 'Horde_Icalendar_Valarm'))
 			{
-				$this->valarm2egw($alarms, $valarm);
+				self::valarm2egw($alarms, $valarm, $event['end'] - $event['start']);
 			}
 		}
 		$event['alarm'] = $alarms;
@@ -2282,19 +2366,6 @@ class calendar_ical extends calendar_boupdate
 			return false;
 		}
 
-		/*
-		$mozillaACK = $component->getAttributeDefault('X-MOZ-LASTACK', null);
-		if ($this->productName == 'lightning' && !isset($mozillaACK))
-		{
-			if ($this->log)
-			{
-				error_log(__FILE__.'['.__LINE__.'] '.__METHOD__.'()' .
-					"X-MOZ-LASTACK found\n",3,$this->logfile);
-			}
-			return false;
-		}
-		*/
-
 		if (!empty($GLOBALS['egw_info']['user']['preferences']['syncml']['minimum_uid_length']))
 		{
 			$minimum_uid_length = $GLOBALS['egw_info']['user']['preferences']['syncml']['minimum_uid_length'];
@@ -2908,6 +2979,31 @@ class calendar_ical extends calendar_boupdate
 				case 'STATUS':	// currently no EGroupware event column, but needed as Android uses it to delete single recurrences
 					$event['status'] = $attributes['value'];
 					break;
+
+				// ignore all PROPS, we dont want to store like X-properties or unsupported props
+				case 'DTSTAMP':
+				case 'SEQUENCE':
+				case 'CREATED':
+				case 'LAST-MODIFIED':
+				case 'DTSTART':
+				case 'DTEND':
+				case 'DURATION':
+				case 'X-LIC-ERROR':	// parse errors from libical, makes no sense to store them
+					break;
+
+				default:	// X- attribute or other by EGroupware unsupported property
+					//error_log(__METHOD__."() $attributes[name] = ".array2string($attributes));
+					// for attributes with multiple values in multiple lines, merge the values
+					if (isset($event['##'.$attributes['name']]))
+					{
+						//error_log(__METHOD__."() taskData['##$attribute[name]'] = ".array2string($taskData['##'.$attribute['name']]));
+						$attributes['values'] = array_merge(
+							is_array($event['##'.$attributes['name']]) ? $event['##'.$attributes['name']]['values'] : (array)$event['##'.$attributes['name']],
+							$attributes['values']);
+					}
+					$event['##'.$attributes['name']] = $attributes['params'] || count($attributes['values']) > 1 ?
+						json_encode($attributes) : $attributes['value'];
+					break;
 			}
 		}
 		// check if the entry is a birthday
diff --git a/calendar/inc/class.calendar_so.inc.php b/calendar/inc/class.calendar_so.inc.php
index 1ff23f3ef3..4c6585eb9e 100644
--- a/calendar/inc/class.calendar_so.inc.php
+++ b/calendar/inc/class.calendar_so.inc.php
@@ -1628,8 +1628,10 @@ ORDER BY cal_user_type, cal_usre_id
 		{
 			foreach ($event['alarm'] as $id => $alarm)
 			{
-				if (is_numeric($id)) unset($alarm['id']);	// unset the temporary id to add the alarm
-
+				if ($alarm['id'] && strpos($alarm['id'], 'cal:'.$cal_id.':') !== 0)
+				{
+					unset($alarm['id']);	// unset the temporary id to add the alarm
+				}
 				if(!isset($alarm['offset']))
 				{
 					$alarm['offset'] = $event['cal_start'] - $alarm['time'];
@@ -1784,7 +1786,7 @@ ORDER BY cal_user_type, cal_usre_id
 	/**
 	 * Combine status, quantity and role into one value
 	 *
-	 * @param string $status
+	 * @param string $status status letter: U, T, A, R
 	 * @param int $quantity =1
 	 * @param string $role ='REQ-PARTICIPANT'
 	 * @return string
@@ -2298,6 +2300,8 @@ ORDER BY cal_user_type, cal_usre_id
 			$this->async->cancel_timer($id);
 		}
 		$alarm['cal_id'] = $cal_id;		// we need the back-reference
+		// add an alarm uid, if none is given
+		if (empty($alarm['uid']) && class_exists('Horde_Support_Uuid')) $alarm['uid'] = (string)new Horde_Support_Uuid;
 		//error_log(__METHOD__.__LINE__.' Save Alarm for CalID:'.$cal_id.'->'.array2string($alarm).'-->'.$id.'#'.function_backtrace());
 		// allways store job with the alarm owner as job-owner to get eg. the correct from address
 		if (!$this->async->set_timer($alarm['time'],$id,'calendar.calendar_boupdate.send_alarm',$alarm,$alarm['owner']))
@@ -2855,7 +2859,7 @@ ORDER BY cal_user_type, cal_usre_id
 	/**
 	 * Moves a datetime to the beginning of the day within timezone
 	 *
-	 * @param egw_time	&time	the datetime entry
+	 * @param egw_time	$time	the datetime entry
 	 * @param string tz_id		timezone
 	 *
 	 * @return DateTime