Found the php error, on a Synology NAS look at /var/log/httpd/user-error_logFastCGI: server "/php-fpm-handler" stderr: PHP message: PHP Fatal error: Class 'Phar' not found in /volume1/web/osTicket-live/include/class.i18n.php on line 309, referer: http://helpdesk/scp/upgrade.phpTurns out Phar (PHP Archive) is not enabled/installed by default.To turn it on, go to control panel, Web Services, PHP Settings tab, and hit the Select PHP extension button.Once I turned on Phar, the upgrade completed without a problem.Thanks for the nudge in the right direction.Credit where it is due: how to turn on Phar on diskstation.