There were some breaking changes in the V4 release, please find the details here:

  
      
      github.com
  
  
    

Release Transformers v4.0.0: Fast tokenizers, model outputs, file reorganization... 108

s/tag/v4.0.0

  Transformers v4.0.0-rc-1: Fast tokenizers, model outputs, file reorganization
Breaking changes since v3.x
Version v4.0.0 introduces several breaking changes that were necessary.
1. AutoTokenizers a...