Game crashes after start
Game launches normally with Neoforge-20.4.12-beta
Modernfix version:modernfix-neoforge-5.10.1+mc1.20.4.jar
crash-2023-12-12_22.19.41-fml.txt

Thanks. It's caused by this NeoForge release being stricter about how events are registered; I will fix it when I have a chance (probably tonight or tomorrow).

Okay, thanks.

Should be fixed in 5.10.2.