The additional *inputs and **kwargs arguments supplied to the from_pretrained() method used to be directly passed to the underlying model's class __init__() method. They are now used to update the model configuration attribute first which can break derived model classes build based on the previous BertForSequenceClassification examples. More precisely, the positional arguments *inputs provided to from_pretrained() are directly forwarded the model __init__() method while the keyword arguments **kwargs (i) which match configuration class attributes are used to update said attributes (ii) which don't match any configuration class attributes are forwarded to the model __init__() method.
Also, while not a breaking change, the serialization methods have been standardized and you probably should switch to the new method save_pretrained(save_directory) if you were using any other serialization method before.
