code: public function run292Update()
  	{
  		$this->Database->query("ALTER TABLE `tl_calendar_events` CHANGE `startTime` `startTime` int(10) unsigned NULL");
  		$this->Database->query("ALTER TABLE `tl_calendar_events` CHANGE `endTime` `endTime` int(10) unsigned NULL");
  		$this->Database->query("ALTER TABLE `tl_calendar_events` CHANGE `startDate` `startDate` int(10) unsigned NULL");
  		$this->Database->query("ALTER TABLE `tl_calendar_events` CHANGE `endDate` `endDate` int(10) unsigned NULL");
  		$this->Database->query("UPDATE tl_calendar_events SET endDate=null WHERE endDate=0");
  	}
docs: Version 2.9.2 update