diff --git a/calendar/inc/class.calendar_ui.inc.php b/calendar/inc/class.calendar_ui.inc.php
index 5446573d60..d455e58bfa 100644
--- a/calendar/inc/class.calendar_ui.inc.php
+++ b/calendar/inc/class.calendar_ui.inc.php
@@ -642,16 +642,20 @@ class calendar_ui
 	 *
 	 * @param int $event_id
 	 * @param Api\DateTime $recurrence_date
+	 * @param array $old_event
 	 *
 	 * @return boolean True if the event was updated, false if it could not be
-	 *	updated or was removed.
+	 *    updated or was removed.
 	 */
-	public function update_client($event_id, Api\DateTime $recurrence_date = null)
+	public function update_client($event_id, Api\DateTime $recurrence_date = null, array $old_event = array())
 	{
-		if(!$event_id) return false;
-		if(is_string($event_id) && strpos($event_id,':') !== FALSE)
+		if(!$event_id)
 		{
-			list($event_id, $date) = explode(':',$event_id);
+			return false;
+		}
+		if(is_string($event_id) && strpos($event_id, ':') !== FALSE)
+		{
+			list($event_id, $date) = explode(':', $event_id);
 			$recurrence_date = new Api\DateTime($date);
 		}
 
@@ -698,6 +702,21 @@ class calendar_ui
 		else if($event['recur_type'] )
 		{
 			$this_month = new Api\DateTime('next month');
+			$data = [];
+			if($old_event && ($old_event['start'] != $event['start'] || $old_event['recur_enddate'] != $event['recur_enddate']))
+			{
+				// Set up to clear old events in case recurrence start/end date changed
+				$old_rrule = calendar_rrule::event2rrule($old_event, true);
+
+				$old_rrule->rewind();
+				do
+				{
+					$occurrence = $old_rrule->current();
+					$data['calendar::' . $old_event['id'] . ':' . $occurrence->format('ts')] = null;
+					$old_rrule->next();
+				}
+				while($old_rrule->valid() && $occurrence <= $this_month);
+			}
 			$rrule = calendar_rrule::event2rrule($event, true);
 			$rrule->rewind();
 			do
@@ -705,10 +724,17 @@ class calendar_ui
 				$occurrence = $rrule->current();
 				$converted = $this->bo->read($event['id'], $occurrence);
 				$this->to_client($converted);
-				$response->generic('data', array('uid' => 'calendar::'.$converted['row_id'], 'data' => $converted));
+				$data['calendar::' . $converted['row_id']] = $converted;
 				$rrule->next();
 			}
-			while ($rrule->valid() && $occurrence <= $this_month );
+			while($rrule->valid() && $occurrence <= $this_month);
+
+			// Now we have to go through and send each one individually, since client side data can't handle more than one
+			foreach($data as $uid => $cal_data)
+			{
+				$response->apply('egw.dataStoreUID', [$uid, $cal_data]);
+			}
+			$response->apply('app.calendar.update_events', [array_keys($data)]);
 		}
 		return true;
 	}
diff --git a/calendar/inc/class.calendar_uiforms.inc.php b/calendar/inc/class.calendar_uiforms.inc.php
index a71a56af23..015c5be07a 100644
--- a/calendar/inc/class.calendar_uiforms.inc.php
+++ b/calendar/inc/class.calendar_uiforms.inc.php
@@ -1007,7 +1007,7 @@ class calendar_uiforms extends calendar_ui
 				$response = Api\Json\Response::get();
 				if($response && $update_type != 'delete' && !$client_updated)
 				{
-					$client_updated = $this->update_client($event['id']);
+					$client_updated = $this->update_client($event['id'], null, $old_event);
 				}
 
 				$msg = $message . ($msg ? ', ' . $msg : '');
diff --git a/calendar/js/app.ts b/calendar/js/app.ts
index 1892521640..38181192d5 100644
--- a/calendar/js/app.ts
+++ b/calendar/js/app.ts
@@ -651,22 +651,34 @@ export class CalendarApp extends EgwApp
 		}
 
 		// Do we already have "fresh" data?  Most user actions give fresh data in response
-		let existing = egw.dataGetUIDdata('calendar::'+pushData.id);
+		let existing = egw.dataGetUIDdata('calendar::' + pushData.id);
 		if(existing && Math.abs(existing.timestamp - new Date().valueOf()) < 1000)
 		{
 			// Update directly
-			this._update_events(this.state, ['calendar::'+pushData.id]);
+			this._update_events(this.state, ['calendar::' + pushData.id]);
 			return;
-		};
+		}
+		;
 
 		// Ask for the real data, we don't have it
-		egw.request("calendar.calendar_ui.ajax_get", [[pushData.id]]).then((data) =>
+		let process_data = (data) =>
 		{
 			// Store it, which will call all registered listeners
 			egw.dataStoreUID(data.uid, data.data);
 
 			// Any existing events were updated.  Run this to catch new events or events moved into view
 			this._update_events(this.state, [data.uid]);
+		}
+		egw.request("calendar.calendar_ui.ajax_get", [[pushData.id]]).then((data) =>
+		{
+			if(typeof data.uid !== "undefined")
+			{
+				return process_data(data)
+			}
+			for(let e of data)
+			{
+				process_data(e);
+			}
 		});
 	}
 
@@ -3736,13 +3748,22 @@ export class CalendarApp extends EgwApp
 				else if(typeof framework !== 'undefined')
 				{
 					framework.applications.calendar.sidemenuEntry.hideAjaxLoader();
-					egw.loading_prompt('calendar',false)
+					egw.loading_prompt('calendar', false)
 
 				}
-			}, this,null
+			}, this, null
 		);
 	}
 
+	/**
+	 * We have a list of calendar UIDs of events that need updating.
+	 * Public wrapper for _update_events so we can call it from server
+	 */
+	update_events(uids : string[])
+	{
+		return this._update_events(this.state, uids);
+	}
+
 	/**
 	 * We have a list of calendar UIDs of events that need updating.
 	 *