diff --git a/config.inc.php.dist b/config.inc.php.dist
index 08d9611..8c7f125 100644
--- a/config.inc.php.dist
+++ b/config.inc.php.dist
@@ -157,6 +157,12 @@ $config['kolab_invitation_calendars'] = false;
 //     )
 // );
 
+// Path used to create new calendars in a CalDav source.
+// The following replacement variables are supported:
+// %u - Source user name
+// %i - Newly generated calendar UUID
+// $config['calendar_caldav_new_calendar_path'] = '/calendars/%u/%i';
+
 // Driver to provide a resource directory ('ldap' is the only implementation yet).
 // Leave empty or commented to disable resources support.
 // $config['calendar_resources_driver'] = 'ldap';
diff --git a/drivers/caldav/SQL/mysql.initial.sql b/drivers/caldav/SQL/mysql.initial.sql
index 92004b2..d460ef9 100644
--- a/drivers/caldav/SQL/mysql.initial.sql
+++ b/drivers/caldav/SQL/mysql.initial.sql
@@ -107,4 +107,5 @@ CREATE TABLE IF NOT EXISTS `caldav_attachments` (
     CONSTRAINT `fk_caldav_attachments_event_id` FOREIGN KEY (`event_id`)
         REFERENCES `caldav_events`(`event_id`) ON DELETE CASCADE ON UPDATE CASCADE
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8 COLLATE utf8_general_ci */;
-REPLACE INTO `system` (`name`, `value`) VALUES ('calendar-caldav-version', '2021082400');
\ No newline at end of file
+
+INSERT INTO `system` (`name`, `value`) VALUES ('calendar-caldav-version', '2021082400');
diff --git a/drivers/caldav/caldav_driver.php b/drivers/caldav/caldav_driver.php
index 71a2162..9739e4c 100644
--- a/drivers/caldav/caldav_driver.php
+++ b/drivers/caldav/caldav_driver.php
@@ -273,10 +273,10 @@ public function create_calendar($cal)
 
             $server_url = self::_encode_url($source['caldav_url']);
             $server_path = rtrim(parse_url($server_url, PHP_URL_PATH), '/');
-            $calId = $this->cal->generate_uid();
-            $path = "/calendars/$source[caldav_user]/$calId";
+            $path = $this->_get_new_calendar_path($source);
 
             self::debug_log("Creating new calendar \"$cal[name]\" with path $path at: " . $server_url);
+
             $client = new caldav_client($server_url, $source['caldav_user'], $source['caldav_pass']);
 
             if($client->create_calendar($server_path . $path, $cal['name'], isset($cal['color']) ? $cal['color'] : 'cc0000')) {
@@ -332,8 +332,6 @@ private function _add_calendars($calendars, $source) {
      */
     public function create_source($source)
     {
-        $source['caldav_url'] = self::_encode_url($source['caldav_url']);
-             
         // Re-discover all existing calendars systematically
         try {               
             $calendars = $this->_autodiscover_calendars($source);
@@ -531,14 +529,12 @@ public function new_event($event)
             if (!$event['calendar'] || !$this->calendars[$event['calendar']])
                 return false;
 
-            if($event = $this->_save_preprocess($event)) {
-                $sync_client = $this->sync_clients[$event["calendar"]];
+            $sync_client = $this->sync_clients[$event["calendar"]];
 
-                // Only push event if caldav_tag is not set to avoid pushing it twice
-                if (isset($event["caldav_tag"]) || ($event = $sync_client->create_event($event)) !== null) {
-                    if ($event_id = $this->_insert_event($event)) {
-                        $this->_update_recurring($event);
-                    }
+            // Only push event if caldav_tag is not set to avoid pushing it twice
+            if (isset($event["caldav_tag"]) || ($event = $sync_client->create_event($event)) !== null) {
+                if ($event_id = $this->_insert_event($event)) {
+                    $this->_update_recurring($event);
                 }
             }
 
@@ -553,7 +549,7 @@ public function new_event($event)
      */
     private function _insert_event(&$event)
     {
-        //$event = $this->_save_preprocess($event);
+        $event = $this->_save_preprocess($event);
 
         //TODO: proper 4 byte character (eg emoticons) handling
         //utf8 in mysql only supports 3 byte characters, so this throws an error if there are emoticons in the description.
@@ -2230,6 +2226,12 @@ private function _perform_updates($updates)
 
         foreach($updates as $update)
         {
+            if(is_null($update['remote_event']))
+            {
+                self::debug_log("No remote_event in update: ".print_r($update, true));
+                continue;
+
+            }
             if($update['remote_event']['allday'])
             {
                 //caldav has exclusive end dates set to midnight of the next day.
@@ -2349,4 +2351,12 @@ private function _encrypt_pass($pass) {
         $p = $e->encrypt($pass);
         return base64_encode($p);
     }
+
+    private function _get_new_calendar_path($source) {
+        $template = $this->rc->config->get('calendar_caldav_new_calendar_path', '/calendars/%u/%i');
+        return strtr($template, [
+                '%u' => $source['caldav_user'],
+                '%i' => $this->cal->generate_uid(),
+        ]);
+    }
 }
diff --git a/drivers/database/SQL/mysql.initial.sql b/drivers/database/SQL/mysql.initial.sql
index 5f6dd60..e2248f2 100644
--- a/drivers/database/SQL/mysql.initial.sql
+++ b/drivers/database/SQL/mysql.initial.sql
@@ -82,4 +82,4 @@ CREATE TABLE IF NOT EXISTS `itipinvitations` (
     REFERENCES `users`(`user_id`) ON DELETE CASCADE ON UPDATE CASCADE
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8 COLLATE utf8_general_ci */;
 
-REPLACE INTO system (name, value) VALUES ('calendar-database-version', '2015022700');
+INSERT INTO system (name, value) VALUES ('calendar-database-version', '2015022700');
diff --git a/drivers/kolab/SQL/mysql.initial.sql b/drivers/kolab/SQL/mysql.initial.sql
index f672fb7..3fca238 100644
--- a/drivers/kolab/SQL/mysql.initial.sql
+++ b/drivers/kolab/SQL/mysql.initial.sql
@@ -29,4 +29,4 @@ CREATE TABLE IF NOT EXISTS `itipinvitations` (
     REFERENCES `users`(`user_id`) ON DELETE CASCADE ON UPDATE CASCADE
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8 COLLATE utf8_general_ci */;
 
-REPLACE INTO system (name, value) VALUES ('calendar-kolab-version', '2014041700');
+INSERT INTO system (name, value) VALUES ('calendar-kolab-version', '2014041700');