diff -urN ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/calendar.php ./plugins/calendar/calendar.php
--- ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/calendar.php	2022-01-14 14:18:46.000000000 +0200
+++ ./plugins/calendar/calendar.php	2022-09-21 01:47:52.574719000 +0300
@@ -389,6 +389,7 @@
         }
 
         $no_override = array_flip((array) $this->rc->config->get('dont_override'));
+$p['current'] = 1;
 
         $p['blocks']['view']['name'] = $this->gettext('mainoptions');
 
@@ -1438,7 +1439,7 @@
     private function event_save_success(&$event, $old, $action, $success)
     {
         // $success is a new event ID
-        if ($success !== true) {
+        if (($action != 'remove') and ($action != 'edit') and ($success !== true)) {
             // send update notification on the main event
             if ($event['_savemode'] == 'future' && !empty($event['_notify'])
                 && !empty($old['attendees']) && !empty($old['recurrence_id'])
@@ -1497,7 +1498,11 @@
             // only notify if data really changed (TODO: do diff check on client already)
             if (!$old || $action == 'remove' || self::event_diff($event, $old)) {
                 $comment = isset($event['_comment']) ? $event['_comment'] : null;
-                $sent    = $this->notify_attendees($event, $old, $action, $comment);
+                if ($action == 'remove') {
+                    $sent = $this->notify_attendees($old, $old, $action, $comment);
+                } else {
+                    $sent = $this->notify_attendees($event, $old, $action, $comment);
+                }
 
                 if ($sent > 0) {
                     $this->rc->output->show_message('calendar.itipsendsuccess', 'confirmation');
diff -urN ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/drivers/calendar_driver.php ./plugins/calendar/drivers/calendar_driver.php
--- ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/drivers/calendar_driver.php	2022-01-14 14:18:46.000000000 +0200
+++ ./plugins/calendar/drivers/calendar_driver.php	2023-04-12 12:09:33.443597000 +0300
@@ -650,7 +650,8 @@
         $year2  = $end->format('Y');
 
         $events = [];
-        $search = mb_strtolower($search);
+//        $search = mb_strtolower($search);
+        $search = (!empty($search) ? mb_strtolower($search) : '');
         $rcmail = rcmail::get_instance();
         $cache  = $rcmail->get_cache('calendar.birthdays', 'db', 3600);
         $cache->expunge();
diff -urN ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/drivers/database/database_driver.php ./plugins/calendar/drivers/database/database_driver.php
--- ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/drivers/database/database_driver.php	2022-01-14 14:18:46.000000000 +0200
+++ ./plugins/calendar/drivers/database/database_driver.php	2022-09-21 01:43:20.883086000 +0300
@@ -112,7 +112,7 @@
     {
         // attempt to create a default calendar for this user
         if (empty($this->calendars)) {
-            if ($this->create_calendar(array('name' => 'Default', 'color' => 'cc0000', 'showalarms' => true))) {
+            if ($this->create_calendar(array('name' => ($this->cal->gettext('default_calendar_name') ? $this->cal->gettext('default_calendar_name') : 'Default'), 'color' => 'cc0000', 'showalarms' => true))) {
                 $this->_read_calendars();
             }
         }
diff -urN ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/localization/en_US.inc ./plugins/calendar/localization/en_US.inc
--- ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/localization/en_US.inc	2022-01-14 14:18:46.000000000 +0200
+++ ./plugins/calendar/localization/en_US.inc	2022-09-21 01:43:20.883521000 +0300
@@ -40,6 +40,7 @@
 // calendar
 $labels['calendar'] = 'Calendar';
 $labels['calendars'] = 'Calendars';
+$labels['default_calendar_name'] = 'Default calendar';
 $labels['category'] = 'Category';
 $labels['categories'] = 'Categories';
 $labels['addcalendar'] = 'Add calendar';
diff -urN ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/localization/ru_RU.inc ./plugins/calendar/localization/ru_RU.inc
--- ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/localization/ru_RU.inc	2022-01-14 14:18:46.000000000 +0200
+++ ./plugins/calendar/localization/ru_RU.inc	2022-09-21 01:43:20.884017000 +0300
@@ -33,6 +33,7 @@
 $labels['weeknoall'] = 'посмотреть в режиме выбора даты и календаря';
 $labels['calendar'] = 'Календарь';
 $labels['calendars'] = 'Календари';
+$labels['default_calendar_name'] = 'Основной календарь';
 $labels['category'] = 'Категория';
 $labels['categories'] = 'Категории';
 $labels['addcalendar'] = 'Добавить календарь';
diff -urN ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/localization/uk_UA.inc ./plugins/calendar/localization/uk_UA.inc
--- ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/localization/uk_UA.inc	2022-01-14 14:18:46.000000000 +0200
+++ ./plugins/calendar/localization/uk_UA.inc	2022-09-21 01:43:20.884414000 +0300
@@ -29,6 +29,7 @@
 $labels['afteraction'] = 'Після того, як запрошення або повідомлення про його зміну оброблено';
 $labels['calendar'] = 'Календар';
 $labels['calendars'] = 'Календарі';
+$labels['default_calendar_name'] = 'Основний календар';
 $labels['category'] = 'Категорія';
 $labels['categories'] = 'Категорії';
 $labels['createcalendar'] = 'Створити новий календар';
diff -urN ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/skins/larry/calendar.css ./plugins/calendar/skins/larry/calendar.css
--- ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/calendar/skins/larry/calendar.css	2022-01-14 14:18:46.000000000 +0200
+++ ./plugins/calendar/skins/larry/calendar.css	2022-09-21 01:43:20.885000000 +0300
@@ -234,7 +234,7 @@
 
 #calendars .treelist.flat li a.calname {
 	left: 24px;
-	right: 42px;
+	right: 52px;
 }
 
 #calendars .treelist li span.handle {
diff -urN ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/libcalendaring/libcalendaring.php ./plugins/libcalendaring/libcalendaring.php
--- ../roundcubemail-plugins-kolab-3.5.11.orig/plugins/libcalendaring/libcalendaring.php	2022-01-14 14:18:46.000000000 +0200
+++ ./plugins/libcalendaring/libcalendaring.php	2023-04-15 15:52:51.725471000 +0300
@@ -1523,7 +1523,7 @@
     public static function to_php_date_format($from)
     {
         // "dd.MM.yyyy HH:mm:ss" => "d.m.Y H:i:s"
-        return strtr(strtr($from, array(
+        return $from === null ? null : strtr(strtr($from, array(
             'YYYY' => 'Y',
             'YY'   => 'y',
             'yyyy' => 'Y',