Bitcoin HWI support freezes as BHWI handoff remains unfinished

Bitcoin HWI, a widely used interface for connecting wallet software to hardware signing devices, is moving toward retirement, while the Rust project its maintainer cited as a promising successor has not yet demonstrated a production handoff.

The maintainer of Bitcoin Core’s Hardware Wallet Interface, or HWI, said on Aug. 18 that the project had effectively been in maintenance mode for years and had largely been a solo effort. HWI will no longer accept new devices or features beyond work needed for MuSig2. Once that work is complete, the maintainer expects to make a release that will likely be the project’s last, then keep HWI in minimal maintenance until a suitable drop-in replacement is ready.

HWI is the bridge that wallet software can use to discover a hardware device, retrieve public keys, display a receive address and send a partially signed Bitcoin transaction to devices such as Ledger, Trezor, Coldcard, BitBox or Jade for approval and signing. The successor candidate named in the notice, BHWI, aims to preserve HWI-style command output with a Rust implementation.

Neither transition is complete. HWI is not archived, no retirement date has been set, and the notice does not say supported hardware wallets will stop working or that users’ bitcoin is at risk. The immediate pressure falls on teams that package HWI, invoke its command line or rely on it to absorb changes in devices, operating systems and vendor protocols.