No Plex App, No Problem: Using Plex as a DLNA/UPnP Server
Plex is an all-in-one media server, streamer, and organizer, but not every platform has a dedicated Plex app. Even with an app available, you might just want a quick and dirty way of streaming your media locally instead.
Digital Network Living Alliance Jason Montoya Plex Media Server Local Plex Content Without Network Living Streaming Than
Source: howtogeek.com