So Fry changed some stuff in the registerEntityRenderingHandler, which breaks stuff for mods using it prior to .1668.

Crashlog: https://gist.github.com/GirafiStudios/fc580e58b19300410b63

I swear they're changing things every other day at this point. I'll take a look

registerEntityRenderingHandler didn't actually work properly before from what I understand :p

Nup, it did. Just had a chat with Fry in IRC now. The only thing that had to be done to work before was move rendering registration for entities into init rather than preinit. By the sounds of it, those changes are about to be reverted.

Ahh okay! Was just what I was told earlier ;)

Fixed, i've been told that for now, both systems will be included. However it is 'encouraged' to register in preinit from now onwards.