You can whitelist certain private local IP's, however for any remote access it must be done through their app.plex.tv website or whatever unless you're going to setup a VPN.

I think that change was made a couple of years ago. I have ran plex on my freenas server for years and had an older version of it. When i upgraded my freenas to use iocage instead of jails recently, i was forced to update plex, and had no clue about this change. I was shocked to say the least and it is absolutely annoying compared how it was. Emby went closed source around the time as well.

I guess as they say, everyone's gotta eat, and filet and caviar are the menu items.