Upgrade from older version appears to complete but Admin Panel > Dashboard > Information still shows the old version number and reports an upgrade available.

If you used a git build, you must run the deploy command (see the osTicket GitHub readme). If you used the official package from osticket.com but the version is still wrong, the old code was not fully replaced. Steps: move all existing code files to a backup folder, download the latest release ZIP from osticket.com, unpack and copy to the site folder, restore only your include/ost-config.php from backup, restart the webserver and PHP-FPM, then retest.