diff --git a/calendar/inc/class.calendar_boupdate.inc.php b/calendar/inc/class.calendar_boupdate.inc.php
index af5035e368..1937ec4751 100644
--- a/calendar/inc/class.calendar_boupdate.inc.php
+++ b/calendar/inc/class.calendar_boupdate.inc.php
@@ -1404,6 +1404,7 @@ class calendar_boupdate extends calendar_bo
 	 */
 	function delete($cal_id,$recur_date=0,$ignore_acl=false,$skip_notification=false)
 	{
+		//error_log(__METHOD__."(cal_id=$cal_id, recur_date=$recur_date, ignore_acl=$ignore_acl, skip_notifications=$skip_notification)");
 		if (!($event = $this->read($cal_id,$recur_date)) ||
 			!$ignore_acl && !$this->check_perms(EGW_ACL_DELETE,$event))
 		{
@@ -1446,7 +1447,10 @@ class calendar_boupdate extends calendar_bo
 		}
 		else	// delete an exception
 		{
-			$event['recur_exception'][] = $recur_date = $this->date2ts($event['start']);
+			// need to read series master, as otherwise existing exceptions will be lost!
+			$recur_date = $this->date2ts($event['start']);
+			$event = $this->read($cal_id);
+			$event['recur_exception'][] = $recur_date;
 			unset($event['start']);
 			unset($event['end']);
 			$this->save($event);	// updates the content-history
diff --git a/calendar/inc/class.calendar_so.inc.php b/calendar/inc/class.calendar_so.inc.php
index 33d266c9d8..2436e50280 100644
--- a/calendar/inc/class.calendar_so.inc.php
+++ b/calendar/inc/class.calendar_so.inc.php
@@ -60,7 +60,7 @@ define('WEEK_s',7*DAY_s);
  * 	- egw_cal_repeats: recur-data: type, optional enddate, etc.
  *  - egw_cal_extra: custom fields (multiple entries per cal_id possible)
  *
- * The new UI, BO and SO classes have a strikt definition, in which time-zone they operate:
+ * The new UI, BO and SO classes have a strict definition, in which timezone they operate:
  *  UI only operates in user-time, so there have to be no conversation at all !!!
  *  BO's functions take and return user-time only (!), they convert internaly everything to servertime, because
  *  SO operates only on server-time
@@ -178,9 +178,8 @@ class calendar_so
 			",$this->dates_table LEFT JOIN $this->repeats_table ON $this->dates_table.cal_id=$this->repeats_table.cal_id".
 			" WHERE $this->cal_table.cal_id=$this->dates_table.cal_id") as $row)
 		{
-			$row['recur_exception'] = $row['recur_exception'] ? explode(',',$row['recur_exception']) : array();
 			if (!$row['recur_type']) $row['recur_type'] = MCAL_RECUR_NONE;
-			$row['alarm'] = array();
+			$row['recur_exception'] = $row['alarm'] = array();
 			$events[$row['cal_id']] = egw_db::strip_array_keys($row,'cal_');
 
 			// if a uid was supplied, convert it for the further code to an id
@@ -193,28 +192,21 @@ class calendar_so
 			if (!isset($event['uid']) || strlen($event['uid']) < $minimum_uid_length)
 			{
 				// event (without uid), not strong enough uid => create new uid
-				$event['uid'] = $GLOBALS['egw']->common->generate_uid('calendar',$event['id']);
+				$event['uid'] = common::generate_uid('calendar',$event['id']);
 				$this->db->update($this->cal_table, array('cal_uid' => $event['uid']),
 					array('cal_id' => $event['id']),__LINE__,__FILE__,'calendar');
 			}
-			if ((int) $recur_date == 0 &&
-				$event['recur_type'] != MCAL_RECUR_NONE &&
-				!empty($event['recur_exception']))
+			if (!(int)$recur_date && $event['recur_type'] != MCAL_RECUR_NONE)
 			{
-				sort($event['recur_exception']);
-				if ($event['recur_exception'][0] < $event['start'])
+				foreach($this->db->select($this->dates_table, 'cal_id,cal_start', array(
+					'cal_id' => $ids,
+					'recur_exception' => true,
+				), __LINE__, __FILE__, false, 'ORDER BY cal_id,cal_start', 'calendar') as $row)
 				{
-					/* Do NOT move start- and end-date, to the earliest exception, as they will NOT be found in CalDAV or ActiveSync, because
-					 * we only recognice recuring events which start before or in the current timerange and end in or after it or have no end-date.
-					 * --> give an error message, as it is a debuging/support nightmare, if this get's silently fixed when reading events.
-					 * No idea how this situation (exceptions before startdate) can be created anyway.
-					 *
-					 * $event['end'] -= $event['start'] - $event['recur_exception'][0];
-					 * $event['start'] = $event['recur_exception'][0];
-					 */
-					error_log(__METHOD__."() recuring event #$event[id]: $event[title] has exceptions before it's startdate ".date('Y-m-d H:i:s',$event['start']));
+					$events[$row['cal_id']]['recur_exception'][] = $row['cal_start'];
 				}
-			}//*/
+				break;	// as above select read all exceptions (and I dont think too short uid problem still exists)
+			}
 		}
 
 		// check if we have a real recurance, if not set $recur_date=0
@@ -424,7 +416,7 @@ class calendar_so
 
 		$cols = self::get_columns('calendar', $this->cal_table);
 		$cols[0] = $this->db->to_varchar($this->cal_table.'.cal_id');
-		$cols = isset($params['cols']) ? $params['cols'] : "$this->repeats_table.recur_type,$this->repeats_table.recur_enddate,$this->repeats_table.recur_interval,$this->repeats_table.recur_data,$this->repeats_table.recur_exception,".implode(',',$cols).",cal_start,cal_end,$this->user_table.cal_recur_date";
+		$cols = isset($params['cols']) ? $params['cols'] : "$this->repeats_table.recur_type,$this->repeats_table.recur_enddate,$this->repeats_table.recur_interval,$this->repeats_table.recur_data,".implode(',',$cols).",cal_start,cal_end,$this->user_table.cal_recur_date";
 
 		$where = array();
 		if (is_array($params['query']))
@@ -639,7 +631,7 @@ class calendar_so
 				// we only select cal_table.cal_id (and not cal_table.*) to be able to use DISTINCT (eg. MsSQL does not allow it for text-columns)
 				foreach(array_keys($selects) as $key)
 				{
-					$selects[$key]['cols'] = "DISTINCT $this->repeats_table.recur_type,$this->repeats_table.recur_enddate,$this->repeats_table.recur_interval,$this->repeats_table.recur_data,$this->repeats_table.recur_exception,".$this->db->to_varchar($this->cal_table.'.cal_id').",cal_start,cal_end,$this->user_table.cal_recur_date";
+					$selects[$key]['cols'] = "DISTINCT $this->repeats_table.recur_type,$this->repeats_table.recur_enddate,$this->repeats_table.recur_interval,$this->repeats_table.recur_data,".$this->db->to_varchar($this->cal_table.'.cal_id').",cal_start,cal_end,$this->user_table.cal_recur_date";
 					if (!$params['enum_recuring'])
 					{
 						$selects[$key]['cols'] = str_replace('cal_start','MIN(cal_start) AS cal_start',$selects[$key]['cols']);
@@ -698,8 +690,7 @@ class calendar_so
 			{
 				$row['participants'] = array();
 			}
-			$row['alarm'] = array();
-			$row['recur_exception'] = $row['recur_exception'] ? explode(',',$row['recur_exception']) : array();
+			$row['recur_exception'] = $row['alarm'] = array();
 
 			// compile a list of recurrences per cal_id
 			if (!in_array($id,(array)$recur_ids[$row['cal_id']])) $recur_ids[$row['cal_id']][] = $id;
@@ -755,6 +746,20 @@ class calendar_so
 					$events[$id]['max_user_modified'] = $modified;
 				}
 			}
+			// query recurrance exceptions, if needed
+			if (!$params['enum_recuring'])
+			{
+				foreach($this->db->select($this->dates_table, 'cal_id,cal_start', array(
+					'cal_id' => $ids,
+					'recur_exception' => true,
+				), __LINE__, __FILE__, false, 'ORDER BY cal_id,cal_start', 'calendar') as $row)
+				{
+					foreach((array)$recur_ids[$row['cal_id']] as $i)
+					{
+						$events[$i]['recurce_id'][] = $row['cal_start'];
+					}
+				}
+			}
 			// max_user_modified for recurring events has to include all recurrences, above code only querys $recur_date!
 			if (!$params['enum_recuring'] && $need_max_user_modified)
 			{
@@ -1070,7 +1075,7 @@ ORDER BY cal_user_type, cal_usre_id
 		// event without uid or not strong enough uid
 		if (!isset($event['cal_uid']) || strlen($event['cal_uid']) < $minimum_uid_length)
 		{
-			$update['cal_uid'] = $event['cal_uid'] = $GLOBALS['egw']->common->generate_uid('calendar',$cal_id);
+			$update['cal_uid'] = $event['cal_uid'] = common::generate_uid('calendar',$cal_id);
 		}
 		// set caldav_name, if not given by caller
 		if (empty($event['caldav_name']) && version_compare($GLOBALS['egw_info']['apps']['calendar']['version'], '1.9.003', '>='))
@@ -1103,11 +1108,13 @@ ORDER BY cal_user_type, cal_usre_id
 			$old_min = (int) $this->db->select($this->dates_table,'MIN(cal_start)',array('cal_id'=>$cal_id),__LINE__,__FILE__,false,'','calendar')->fetchColumn();
 			$old_duration = (int) $this->db->select($this->dates_table,'MIN(cal_end)',array('cal_id'=>$cal_id),__LINE__,__FILE__,false,'','calendar')->fetchColumn() - $old_min;
 			$old_repeats = $this->db->select($this->repeats_table,'*',array('cal_id' => $cal_id),__LINE__,__FILE__,false,'','calendar')->fetch();
-			$old_exceptions = $old_repeats['recur_exception'] ? explode(',',$old_repeats['recur_exception']) : array();
-			if (!empty($old_exceptions))
+			$old_exceptions = array();
+			foreach($this->db->select($this->dates_table, 'cal_start', array(
+				'cal_id' => $cal_id,
+				'recur_exception' => true
+			), __LINE__, __FILE__, false, 'ORDER BY cal_start', 'calendar') as $row)
 			{
-				sort($old_exceptions);
-				if ($old_min > $old_exceptions[0]) $old_min = $old_exceptions[0];
+				$old_exceptions[] = $row['cal_start'];
 			}
 
 			$event['recur_exception'] = is_array($event['recur_exception']) ? $event['recur_exception'] : array();
@@ -1116,8 +1123,10 @@ ORDER BY cal_user_type, cal_usre_id
 				sort($event['recur_exception']);
 			}
 
-			$where = array('cal_id' => $cal_id,
-							'cal_recur_date' => 0);
+			$where = array(
+				'cal_id' => $cal_id,
+				'cal_recur_date' => 0,
+			);
 			$old_participants = array();
 			foreach ($this->db->select($this->user_table,'cal_user_type,cal_user_id,cal_status,cal_quantity,cal_role', $where,
 				__LINE__,__FILE__,false,'','calendar') as $row)
@@ -1197,14 +1206,18 @@ ORDER BY cal_user_type, cal_usre_id
 				// truncate recurrences by given exceptions
 				if (count($event['recur_exception']))
 				{
-					// added and existing exceptions: delete the execeptions from the user and dates table, it could be the first time
+					// added and existing exceptions: delete the execeptions from the user table, it could be the first time
 					$this->db->delete($this->user_table,array('cal_id' => $cal_id,'cal_recur_date' => $event['recur_exception']),__LINE__,__FILE__,'calendar');
-					$this->db->delete($this->dates_table,array('cal_id' => $cal_id,'cal_start' => $event['recur_exception']),__LINE__,__FILE__,'calendar');
+					// update recur_exception flag based on current exceptions
+					$this->db->update($this->dates_table, 'recur_exception='.$this->db->expression($this->dates_table,array(
+						'cal_start' => $event['recur_exception'],
+					)), array(
+						'cal_id' => $cal_id,
+					), __LINE__, __FILE__, 'calendar');
 				}
 			}
 
 			// write the repeats table
-			$event['recur_exception'] = empty($event['recur_exception']) ? null : implode(',',$event['recur_exception']);
 			unset($event[0]);	// unset the 'etag=etag+1', as it's not in the repeats table
 			$this->db->insert($this->repeats_table,$event,array('cal_id' => $cal_id),__LINE__,__FILE__,'calendar');
 		}
diff --git a/calendar/setup/setup.inc.php b/calendar/setup/setup.inc.php
index be7330243e..c85a3276fe 100755
--- a/calendar/setup/setup.inc.php
+++ b/calendar/setup/setup.inc.php
@@ -10,7 +10,7 @@
  */
 
 $setup_info['calendar']['name']    = 'calendar';
-$setup_info['calendar']['version'] = '1.9.004';
+$setup_info['calendar']['version'] = '1.9.005';
 $setup_info['calendar']['app_order'] = 3;
 $setup_info['calendar']['enable']  = 1;
 $setup_info['calendar']['index']   = 'calendar.calendar_uiviews.index';
@@ -70,3 +70,4 @@ $setup_info['calendar']['check_install'] = array(
 );
 
 
+
diff --git a/calendar/setup/tables_current.inc.php b/calendar/setup/tables_current.inc.php
index aa17d845ee..51eb97b535 100644
--- a/calendar/setup/tables_current.inc.php
+++ b/calendar/setup/tables_current.inc.php
@@ -62,7 +62,6 @@ $phpgw_baseline = array(
 			'recur_enddate' => array('type' => 'int','precision' => '8'),
 			'recur_interval' => array('type' => 'int','precision' => '2','default' => '1'),
 			'recur_data' => array('type' => 'int','precision' => '2','default' => '1'),
-			'recur_exception' => array('type' => 'text','comment' => 'comma-separated start timestamps of exceptions')
 		),
 		'pk' => array('cal_id'),
 		'fk' => array(),
@@ -100,11 +99,12 @@ $phpgw_baseline = array(
 		'fd' => array(
 			'cal_id' => array('type' => 'int','precision' => '4','nullable' => False),
 			'cal_start' => array('type' => 'int','precision' => '8','nullable' => False,'comment' => 'starttime in server time'),
-			'cal_end' => array('type' => 'int','precision' => '8','nullable' => False,'comment' => 'endtime in server time')
+			'cal_end' => array('type' => 'int','precision' => '8','nullable' => False,'comment' => 'endtime in server time'),
+			'recur_exception' => array('type' => 'bool','nullable' => False,'default' => '','comment' => 'date is an exception')
 		),
 		'pk' => array('cal_id','cal_start'),
 		'fk' => array(),
-		'ix' => array(),
+		'ix' => array(array('recur_exception','cal_id')),
 		'uc' => array()
 	),
 	'egw_cal_timezones' => array(
diff --git a/calendar/setup/tables_update.inc.php b/calendar/setup/tables_update.inc.php
index a39e3f431d..1a77264cb3 100644
--- a/calendar/setup/tables_update.inc.php
+++ b/calendar/setup/tables_update.inc.php
@@ -2076,3 +2076,54 @@ function calendar_upgrade1_9_003()
 
 	return $GLOBALS['setup_info']['calendar']['currentver'] = '1.9.004';
 }
+
+/**
+ * Store exceptions as flag in egw_cal_dates.recur_exception, instead of egw_cal_repleats.recur_exception
+ *
+ * Keeps information of original start in egw_cal_dates (if first recurrance got deleted) and allows for unlimited number of exceptions.
+ */
+function calendar_upgrade1_9_004()
+{
+	$GLOBALS['egw_setup']->oProc->AddColumn('egw_cal_dates','recur_exception',array(
+		'type' => 'bool',
+		'default' => '',
+		'null' => false,
+		'comment' => 'date is an exception'
+	));
+
+	// migrate existing exceptions to egw_cal_dates
+	foreach($GLOBALS['egw_setup']->db->select('egw_cal_repeats',
+		'egw_cal_repeats.cal_id AS cal_id,egw_cal_repeats.recur_exception AS recur_exception,MIN(cal_start) AS cal_start,MIN(cal_end) AS cal_end',
+		'egw_cal_repeats.recur_exception IS NOT NULL', __LINE__, __FILE__, false,
+		'GROUP BY egw_cal_repeats.cal_id,egw_cal_repeats.recur_exception', 'calendar', '',
+		'JOIN egw_cal_dates ON egw_cal_repeats.cal_id=egw_cal_dates.cal_id') as $row)
+	{
+		foreach($row['recur_exception'] ? explode(',', $row['recur_exception']) : array() as $recur_exception)
+		{
+			$GLOBALS['egw_setup']->db->insert('egw_cal_dates', array(
+				'cal_id' => $row['cal_id'],
+				'cal_start' => $recur_exception,
+				'cal_end' => $recur_exception+$row['cal_end']-$row['cal_start'],
+				'recur_exception' => true,
+			), false, __LINE__, __FILE__, 'calendar');
+		}
+	}
+	$GLOBALS['egw_setup']->oProc->CreateIndex('egw_cal_dates', array('recur_exception', 'cal_id'));
+
+	$GLOBALS['egw_setup']->oProc->DropColumn('egw_cal_repeats', array(
+		'fd' => array(
+			'cal_id' => array('type' => 'int','precision' => '4','nullable' => False),
+			'recur_type' => array('type' => 'int','precision' => '2','nullable' => False),
+			'recur_enddate' => array('type' => 'int','precision' => '8'),
+			'recur_interval' => array('type' => 'int','precision' => '2','default' => '1'),
+			'recur_data' => array('type' => 'int','precision' => '2','default' => '1'),
+		),
+		'pk' => array('cal_id'),
+		'fk' => array(),
+		'ix' => array(),
+		'uc' => array()
+	), 'recur_exception');
+
+	return $GLOBALS['setup_info']['calendar']['currentver'] = '1.9.005';
+}
+