In the plex server folders there is one that contain .exe for all the server versions you had. Save a previous version (all to be sure), than uninstall the plex server from control panel, (not by deleting or using some fancy uninstaller), than run that version you want and you will have the old server. Check to allow unsecured connections (i had chose “preferred” option) and check to allow unsecured connection from the TV’s IP (or from the entire subnet). After that start plex app on TV and chose manual config for plex server.
