# Hugging Face Transformers v4.55.3 — Release & Upgrade Intelligence
- **Product:** Hugging Face Transformers (https://huggingface.co)
- **Version:** v4.55.3
- **Released:** Aug 21, 2025
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/transformers/updates/v4.55.3/

## Executive Summary (TL;DR)
Hugging Face Transformers v4.55.3. Source highlight: Patch release 4.55.3

## Bug Fixes
- FlashAttention-2 / Ascend NPU – Fix “unavailable” runtime error (#40151)
- FlashAttention kwargs – Revert FA kwargs preparation to resolve regression (#40161)
- FSDP (generic-task models) – Fix sharding/runtime issues (#40191)
- GPT-OSS / MXFP4 – Ensure swiglu_limit is correctly passed through (#40197)
- Mamba – Fix cache handling to prevent stale/incorrect state (#40203)
- Misc – Minor follow-up fix addressing #40262

## Upgrade Command
```bash
python -m pip install 'transformers==4.55.3'
```