# Hugging Face Transformers v4.15.0 — Release & Upgrade Intelligence
- **Product:** Hugging Face Transformers (https://huggingface.co)
- **Version:** v4.15.0
- **Released:** Dec 22, 2021
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/transformers/updates/v4.15.0/

## Executive Summary (TL;DR)
Hugging Face Transformers v4.15.0. Source highlight: WavLM was proposed in WavLM: Large-Scale Self-Supervised Pre-Training for Full Stack Speech Processing by Sanyuan Chen, Chengyi Wang, Zhengyang Chen, Yu Wu, Shujie Liu, Zhuo Chen, Jinyu Li, Naoyuki Kanda, Takuya Yoshioka, Xiong Xiao, Jian Wu, Long Zhou, Shuo Ren, Yanmin Qian, Yao Qian, Jian Wu, Mich

## New Features
- Add WavLM
- Add Speaker Diarization and Verification heads
- Add SD and SV heads for WavLM
- Add an argument to set bucket_cap_mb for PyTorch DDP
- Add 'with torch.no_grad()' to DeBERTa integration test forward pass
- Add 'with torch.no_grad()' to BERT integration test forward pass

## Bug Fixes
- Fix the build documentation job
- Train step fix
- Fix Perceiver multi GPU test
- [WavLM] Fix slow tests
- Fix dead link to benchmarks.ipynb
- Fix the value error typo of AdamW's betas' valid values checking

## Upgrade Command
```bash
python -m pip install 'transformers==4.15.0'
```