IP address logging in Play History Log

The play history shows player and platform used and when movie was played, but its missing very critical info, which is the IP address of the user accessing the service.

For instance I invited a lot of friends to use my server, but I believe some of them shared their account with someone else, but I’m unable to prove it.

Plex already displays user IP address during playback but that information is not being logged.
If a plex would log those IP addresses, you could easy look thru the logs to find out from where someone accessed your server.

I think this feature is nore important that knowind which platform or player user used to watch the movie

Try Tautulli.
Also, user’s IP addresses change all the time. Imagine a user who has a TV at home, but also a mobile phone with the Plex app. These 2 devices will definitely have different IP addresses, (at least as long as the phone is outside his home network).

Residential internet connections change their public IP addresses frequently. It is very rare to have a fixed IP address for this type of connection.