MPT base: MPT base pre-trained models on next token prediction 
MPT instruct: MPT base models fine-tuned on instruction based tasks
MPT storywriter: MPT base models fine-tuned for 2500 steps on 65k-token excerpts of fiction books contained in the books3 corpus, this enables the model to handle very long sequences

The original code is available at the  llm-foundry repository.
Read more about it in the release blogpost
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