Crash when using mixinbooter 8.0+ version.
Log:
(https://pastebin.com/Ff0EXn0T)

Note for anyone still looking at this issue: fixed by 61cd82f (in 8.4)

Can't really support SpongeForge at the moment, since they package their mixins already.

MixinBooter 7.1 is compatible. The issue is likely the new mixin version in 8.0.