Heuristic:Huggingface Peft Warning Deprecated Bone
| Knowledge Sources | |
|---|---|
| Domains | Parameter_Efficient_Finetuning, Migration |
| Last Updated | 2026-02-07 14:00 GMT |
Overview
Deprecation warning: the Bone (Block Affine) PEFT method is scheduled for removal in PEFT v0.19.0, users should migrate to MissConfig.
Description
The Bone tuner emits a DeprecationWarning during BoneConfig.__post_init__, stating that Bone will be removed in PEFT v0.19.0. The recommended replacement is MissConfig (Mixture of Subspace Shards). A conversion script is provided at scripts/convert-bone-to-miss.py to migrate existing Bone checkpoints to the MiSS format.
Usage
Consult this heuristic when working with or encountering Bone-related code. Any new projects should use MissConfig instead. Existing Bone checkpoints should be converted using the provided migration script before the deprecation deadline.
The Insight (Rule of Thumb)
- Action: Replace BoneConfig with MissConfig in all new code.
- Value: Use scripts/convert-bone-to-miss.py to migrate existing Bone adapter checkpoints.
- Trade-off: None significant; MiSS is the direct successor with equivalent or improved functionality.
- Deadline: PEFT v0.19.0 will remove Bone entirely.
Reasoning
The PEFT maintainers have consolidated the Bone adapter into the MiSS (Mixture of Subspace Shards) method, which generalizes the block affine approach. The deprecation is explicitly coded in src/peft/tuners/bone/config.py (lines 126-129) via warnings.warn(). Continuing to use Bone past v0.19.0 will result in import errors or missing functionality.