# Hugging Face Transformers v0.5.1 — Release & Upgrade Intelligence
- **Product:** Hugging Face Transformers (https://huggingface.co)
- **Version:** v0.5.1
- **Released:** Feb 13, 2019
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/transformers/updates/v0.5.1/

## Executive Summary (TL;DR)
Hugging Face Transformers v0.5.1. Source highlight: Mostly a bug fix update for loading the `TransfoXLModel` from s3:

## New Features
- Added a fallback of `OpenAIGPTTokenizer` on BERT's `BasicTokenizer` when SpaCy and ftfy are not installed. Using BERT's `BasicTokenizer` instead of SpaCy should be fine in most cases as long as you have a relatively clean input (SpaCy+ftfy were included to exactly reproduce the paper's pre-processing steps on the Toronto Book Corpus) and this also let us use the `never_split` option to avoid splitting special tokens like `[CLS], [SEP]...` which is easier than adding the tokens after tokenization

## Bug Fixes
- Fixes a bug in the loading of the pretrained `TransfoXLModel` from the s3 dump (which is a converted `TransfoXLLMHeadModel`) in which the weights were not loaded.

## Upgrade Command
```bash
python -m pip install 'transformers==0.5.1'
```