/**
* Reset values that shall not be updated by the user directly
* @param \OCA\Calendar\ICalendar &$new
* @param \OCA\Calendar\ICalendar $old
*/
private function resetReadOnlyProperties(ICalendar &$new, ICalendar $old)
{
$new->setUserId($old->getUserId());
$new->setOwnerId($old->getOwnerId());
$new->setCruds($old->getCruds());
$new->setCtag($old->getCtag());
}