With a newer version of Forge the mod crashes at startup.

Maybe these changes cause the problem:

Build: 1.16.1-32.0.108 - Sun Aug 09 20:05:01 GMT 2020
David Quintana:
Fix ModelRegistryEvent firing every time resources reload instead of just once.

Build: 1.16.1-32.0.107 - Sat Aug 08 01:00:42 GMT 2020
David Quintana:
Move ModelRegistryEvent invocation to when the model loading is about to start.
Freeze the ModelLoaderRegistry right after this event happens, just before model loading actually begins.
This means ModelRegistryEvent is now the correct place to register loaders, as it was intended.
This is a slight breaking change, but any mod that used FMLClientSetupEvent before will need to be updated regardless due to the existing race condition.

fixed