Bitcoin Core’s Hardware Wallet Interface Enters Maintenance Mode, Raising Compatibility Concerns for Wallets

Bitcoin Core’s Hardware Wallet Interface (HWI), the Python‑based bridge that lets wallet software communicate with hardware signing devices, has entered a maintenance freeze. The maintainer announced that HWI will no longer add support for new devices or features beyond the work required for MuSig2, after which a final release is expected.

Why the change matters

HWI provides a common command‑line and library interface for discovering hardware wallets, retrieving public keys, displaying receive addresses, and signing partially signed Bitcoin transactions. It supports devices such as Ledger, Trezor, Coldcard, BitBox, KeepKey, Blockstream Jade and others. Because many wallets depend on HWI either directly (as a Python dependency) or via wrappers around its command line, the freeze creates a succession problem: downstream projects must either adopt a new implementation, maintain a fork, or risk losing support for future hardware models.

Impact on popular wallets

• Specter Desktop pins HWI 3.1.0 and will need to repackage a replacement and retest device discovery, address display and signing.
• BTCPay Server Vault wraps HWI’s command line; its wrapper must be adapted and verified against the new bridge.
• Wasabi Wallet ties hardware‑wallet support to HWI and will need to replace or maintain the executable across platforms.
• Sparrow Wallet uses a Java port (Lark) derived from HWI, meaning it must continue maintaining its own stack.

Proposed successor: BHWI

BHWI is a Rust implementation that aims to preserve HWI‑style command output while offering reproducible builds. Its test suite runs parity checks against HWI 3.2.0 for BitBox02, Coldcard, Ledger and Jade devices. However, BHWI is still labeled “work in progress,” and no wallet has yet adopted it as a production replacement.

What wallet developers need to do

1. Validate that BHWI (or another replacement) matches the required device‑operation pairs for their supported hardware.
2. Update packaging pipelines to include the new binary and ensure compatibility on all host platforms (including Apple Silicon).
3. Perform integration testing of the external‑signer contract used by Bitcoin Core and any custom command‑line wrappers.

Future outlook

The final HWI release will likely mark a fixed upstream boundary. After that, any new device, firmware change, or operating‑system update will require downstream patches without a normal upstream path. Wallet projects that continue to rely on HWI must plan for either adopting BHWI, maintaining their own forks, or accepting limited hardware support.