# Hugging Face Transformers v4.56.1 — Release & Upgrade Intelligence
- **Product:** Hugging Face Transformers (https://huggingface.co)
- **Version:** v4.56.1
- **Released:** Sep 04, 2025
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/transformers/updates/v4.56.1/

## Executive Summary (TL;DR)
Hugging Face Transformers v4.56.1. Source highlight: Patch release v4.56.1

## Bug Fixes
- Fix broken Llama4 accuracy in MoE part (#40609)
- fix pipeline dtype (#40638)
- Fix self.dropout_p is not defined for SamAttention/Sam2Attention (#40667)
- Fix backward compatibility with accelerate in Trainer (#40668)
- fix broken offline mode when loading tokenizer from hub (#40669)
- [Glm4.5V] fix vLLM support (#40696)

## Upgrade Command
```bash
python -m pip install 'transformers==4.56.1'
```