Web app says server upgrade available, but how to do it?

which update channel are you using for your Plex Media server?

  • Plex Media Server 1.14.1.5488 is the latest public release available to all Plex users
  • Plex Media Server 1.15.1.710 is the latest update for Plex Pass members using the beta update channel
  • The linux repo is only available for public releases – however occasionally it’s slightly behind or takes a little longer to be updated… that’s probably why it considers 1.14.0.5470 to be up-to-date

As for the manual update… did you run dpkg -i with admin permission / sudo?
If the update is properly applied, app.plex.tv/desktop > settings > server > general should show the version you’re running.

You’re not by chance running multiple servers with one still being on 1.14.0?