I search for PlexMediaServer-1.14.1.5488-cc260c476-x86.qpkg for a qnap NAS TS809+
In plex it say there is a new version, download manually. Try to install this version today, it remove the working version from the NAS and try to install the new before saying impossible.
On qnap repository it was a very old version. I don’t have this version on computer. If somebody has a link ?