Hardware Wallet Interface halts support for new Bitcoin devices

The Hardware Wallet Interface (HWI), a critical software layer that enables communication between Bitcoin wallet software and hardware signing devices, is moving into a maintenance-only mode. On August 18, the HWI maintainer, Ava Chow, announced that the project will no longer accept new features, feature requests, or pull requests for new hardware devices, with the exception of work required for MuSig2 support.

HWI serves as a bridge for devices such as Ledger, Trezor, Coldcard, BitBox, and Jade, allowing them to detect public keys and sign partially signed Bitcoin transactions (PSBT). While existing supported devices will continue to function, the decision creates a bottleneck for the integration of future hardware models and firmware updates into the common repository.

The industry response is divided. Some wallet implementations, such as Specter Desktop and BTCPay Server, rely heavily on HWI, while others like Sparrow use Lark, a Java-based port of HWI, to maintain a separate path. A potential successor, BHWI, is being developed using Rust to provide a more modern, asynchronous interface, though it is currently still a work in progress.