●Change8

Migrating to Transformers v4.55.2

Version v4.55.2 introduces 1 breaking change. This guide details how to update your code.

Released: 8/13/2025

1
Breaking Changes
1
Migration Steps
2
Affected Symbols

⚠️ Check Your Code

If you use any of these symbols, you need to read this guide:

modeling_flash_attention_utilsprepare_fa_kwargs_from_position_ids

Breaking Changes

●Issue #1

The 4.55.1 release was broken for Flash Attention 2 (FA2) generations due to a missing import: 'prepare_fa_kwargs_from_position_ids'.

Migration Steps

  1. 1
    Upgrade from 4.55.1 to 4.55.2 immediately if using Flash Attention 2.

Release Summary

Patch release 4.55.2 fixes a critical regression in Flash Attention 2 (FA2) generations caused by a missing utility import in version 4.55.1.

Need More Details?

View the full release notes and all changes for Transformers v4.55.2.

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