@voodle65: you could check if you can access the Plex Media Server using a DLNA client (e.g. VLC for tvOS). Alternatively you could consider adding a micro computer like a NUC to run your Plex Media Server while keeping the old QNAP as a storage unit (e.g. if you have a spare computer or don’t mind the invest).
On a more general note:
If you can no longer update your Plex Media Server (e.g. because your platform does not support newer versions), make sure to disable automatic app updates!
This will not help the OP but should be an important consideration for other users with an outdated version of Plex Media Server they can no longer update.
Plex had announced this change some time ago:
- in the release announcements for Plex for iOS / tvOS 7.4 (“this is the last version supporting servers older than 1.15.2”)
- by sending mails where they could identify users of old servers (pre 1.15.2) as well as a dedicated announcement in the forum
