diff --git a/calendar/inc/class.calendar_uiforms.inc.php b/calendar/inc/class.calendar_uiforms.inc.php
index 69c04ec054..0f201fc237 100644
--- a/calendar/inc/class.calendar_uiforms.inc.php
+++ b/calendar/inc/class.calendar_uiforms.inc.php
@@ -2243,19 +2243,6 @@ class calendar_uiforms extends calendar_ui
 				{
 					$master = $this->bo->read($event['uid']);
 				}
-				$all_participants = ($event['participants'] ?? []) + ($existing_event['participants'] ?? []);
-				$event['participantChanges'] = array_map(function($uid, $status) use ($existing_event, $event) {
-					return [
-						'changed' => !isset($event['participants'][$uid]) ? 'meetingRequestParticipantDeleted' :
-							(!isset($existing_event['participants'][$uid]) ? 'meetingRequestChanged' :
-								($status !== $existing_event['participants'][$uid] ? 'meetingRequestChangedStatus' : '')),
-						'label' => $this->bo->participant_name($uid),
-						'status' => lang($this->bo->verbose_status[calendar_so::split_status($status, $quantity, $role)]),
-						'role' => $role === 'REQ-PARTICIPANT' ? '' : lang($this->bo->roles[$role] ??
-							(substr($role,0,6) === 'X-CAT-' && ($cat_id = (int)substr($role,6)) > 0 ?
-								$GLOBALS['egw']->categories->id2name($cat_id) : str_replace('X-','',$role))),
-					];
-				}, array_keys($all_participants), $all_participants);
 
 				switch(strtolower($ical_method))
 				{
@@ -2370,14 +2357,19 @@ class calendar_uiforms extends calendar_ui
 			{
 				$readonlys['button[cancel]'] = true;	// no way to remove a canceled event not in calendar
 			}
-			$event['participant_types'] = array();
-			foreach($event['participants'] as $uid => $status)
-			{
-				$user_type = $user_id = null;
-				calendar_so::split_user($uid, $user_type, $user_id);
-				$event['participants'][$uid] = $event['participant_types'][$user_type][$user_id] =
-					$status && $status !== 'X' ? $status : 'U';	// X --> no status given --> U = unknown
-			}
+			$all_participants = ($event['participants'] ?? []) + ($existing_event['participants'] ?? []);
+			$event['participantChanges'] = array_map(function($uid, $status) use ($existing_event, $event) {
+				return [
+					'changed' => !isset($event['participants'][$uid]) ? 'meetingRequestParticipantDeleted' :
+						(!isset($existing_event) ? '' : (!isset($existing_event['participants'][$uid]) ? 'meetingRequestChanged' :
+							($status !== $existing_event['participants'][$uid] ? 'meetingRequestChangedStatus' : ''))),
+					'label' => $this->bo->participant_name($uid),
+					'status' => lang($this->bo->verbose_status[calendar_so::split_status($status, $quantity, $role)]),
+					'role' => $role === 'REQ-PARTICIPANT' ? '' : lang($this->bo->roles[$role] ??
+						(substr($role,0,6) === 'X-CAT-' && ($cat_id = (int)substr($role,6)) > 0 ?
+							$GLOBALS['egw']->categories->id2name($cat_id) : str_replace('X-','',$role))),
+				];
+			}, array_keys($all_participants), $all_participants);
 			//error_log(__METHOD__."(...) parsed as ".array2string($event));
 			$event['recure'] = $this->bo->recure2string($master ?? null ?: $event);
 			if (!empty($master)) unset($event['changed']['recure']);