My friend with an M1 Mac, whose game crashes with this mod, would like to play on my modded server. However, when he tries to join without the mod, the server kicks him:

[Netty Epoll Client IO #2/ERROR] [ne.mi.ne.HandshakeHandler/FMLHANDSHAKE]: Channels [plasmo:voice] rejected their client side version number
[Netty Epoll Client IO #2/ERROR] [ne.mi.ne.HandshakeHandler/FMLHANDSHAKE]: Terminating connection with server, mismatched mod list

...even though the mod claims "Players without the mod are still able to join and play as usual."
I couldn't find anywhere in the configs to disable kicking clients without the mod, either.

Welp, I ended up recompiling the mod myself lol. It just needed a network setting changed, I did a pull request for it