We are also changing how remote playback works for streaming personal media (that is, playback when not on the same local network as the server). The reality is that we need more resources to continue putting forth the best personal media experience, and as a result, we will no longer offer remote playback as a free feature. This—alongside the new Plex Pass pricing—will help provide those resources. This change will apply to the future release of our new Plex experience for mobile and other platforms.
A VPN Server on the server or home network (look into PiVPN for instance), and a VPN Client on clients (look at openvpn for instance).
Good luck and let me know if you have any further questions - I’m more than happy to answer!