ACM 4.7 flight simulator also has LAN multiplayer game support in 1994[0], but in 1995 re-implemented multiplayer via own DIS protocol in ACM 4.8 release (see `dislib.doc` in ACM 4.8 and 5.0 release tarballs).[1,2,3]

Actively maintained ACM 6.0 uses DIS as well.[4,5,6]

[0] https://www.ibiblio.org/pub/Linux/games/multiplayer

[1] http://web.archive.org/web/19981201235648/http://www.websimu...

[2] https://wiki.flightgear.org/ACM_%28flight_sim%29

[3] http://web.archive.org/web/20180614080440/http://www.flightg...

[4] http://cvs.icosaedro.it:8080/viewvc/public/acm/CHANGES.txt?v...

[5] http://www.icosaedro.it/acm/download.html

[6] https://libregamewiki.org/ACM