This week’s newsletter includes our regular sections describing changes to services and client software, announcing new releases and release candidates, and summarizing recent changes to popular Bitcoin infrastructure software.

News

No significant news this week was found in any of our sources.

Changes to services and client software

In this monthly feature, we highlight interesting updates to Bitcoin wallets and services.

• ● Cake Wallet added payjoin v2 support: Cake Wallet v4.28.0 adds the ability to receive payments using the payjoin v2 protocol.

• ● Sparrow adds pay-to-anchor features: Sparrow 2.2.0 displays and can send pay-to-anchor (P2A) outputs.

• ● Safe Wallet 1.3.0 released: Safe Wallet is a desktop multisig wallet with hardware signing device support that added CPFP fee bumping for incoming transactions in 1.3.0.

• ● COLDCARD Q v1.3.2 released: COLDCARD Q’s v1.3.2 release includes additional multisig spending policy support and new features for sharing sensitive data.

• ● Transaction batching using payjoin: Private Pond is an experimental implementation of a transaction batching service that uses payjoin to generate smaller transactions that pay less in fees.

• ● JoinMarket Fidelity Bond Simulator: The JoinMarket Fidelity Bond Simulator provides tools for JoinMarket participants to simulate their performance in the market based on fidelity bonds.

• ● Bitcoin opcodes documented: The Opcode Explained website documents each Bitcoin script opcode.

• ● Bitkey code open sourced: The Bitkey hardware signing device announced their source code is open-source for non-commercial uses.

Releases and release candidates

New releases and release candidates for popular Bitcoin infrastructure projects. Please consider upgrading to new releases or helping to test release candidates.

• ● LND 0.19.0-beta is the latest major release of this popular LN node. Its contains many improvements and bug fixes, including new RBF-based fee bumping for cooperative closes.

• ● Core Lightning 25.05rc1 is a release candidate for the next major version of this popular LN node implementation.

Notable code and documentation changes

Notable recent changes in Bitcoin Core, Core Lightning, Eclair, LDK, LND, libsecp256k1, Hardware Wallet Interface (HWI), Rust Bitcoin, BTCPay Server, BDK, Bitcoin Improvement Proposals (BIPs), Lightning BOLTs, Lightning BLIPs, Bitcoin Inquisition, and BINANAs.

• ● Bitcoin Core #32423 removes the deprecation notice for rpcuser/rpcpassword and replaces it with a security warning about storing cleartext credentials in the configuration file. This option was originally deprecated when rpcauth was introduced in Bitcoin Core #7044, which supports multiple RPC users and hashes its cookie. The PR also adds a random 16-byte salt to credentials from both methods and hashes them before they’re stored in memory.

• ● Bitcoin Core #31444 extends the TxGraph class (see Newsletter #348) with three new helper functions: GetMainStagingDiagrams() returns the divergences of clusters between the main and staged feerate diagrams, GetBlockBuilder() iterates through graph chunks (sub-cluster feerate-sorted groupings) from highest to lowest feerate for optimized block construction, and GetWorstMainChunk() pinpoints the lowest feerate chunk for eviction decisions. This PR is one of the final building blocks of the full initial implementation of the cluster mempool project.

• ● Core Lightning #8140 enables peer storage of channel backups by default (see Newsletter #238), making it viable for large nodes by limiting storage to peers with current or past channels, caching backups and peer lists in memory instead of making repeated listdatastore/listpeerchannels calls, capping concurrent backup uploads at two peers, skipping backups larger than 65 kB, and randomizing peer selection when sending.

• ● Core Lightning #8136 updates the exchange of announcement signatures to occur when the channel is ready rather than after six blocks, to align with the recent BOLTs #1215 specification update. It’s still required to wait six blocks to announce the channel.

• ● Core Lightning #8266 adds an update command to the Reckless plugin manager (see Newsletter #226) that updates a specified plugin or all installed plugins if none is specified, except those installed from a fixed Git tag or commit. This PR also extends the install command to take a source path or URL in addition to a plugin name.

• ● Core Lightning #8021 finalizes splicing interoperability with Eclair (see Newsletter #331) by fixing the rotation of remote funding keys, resending splice_locked on channel re-establishment to cover cases where it was originally missed (see Newsletter #345), relaxing the requirement that commitment-signed messages arrive in a particular order, enabling receiving and initiating splice RBF transactions, automatically converting outgoing PSBTs to version 2 when needed, and other refactoring changes.

• ● Core Lightning #8226 implements BIP137 by adding a new signmessagewithkey RPC command that allows users to sign messages with any key from the wallet by specifying a Bitcoin address. Previously, signing a message with a Core Lightning key required finding the xpriv and the key index, deriving the private key with an external library, and then signing the message with Bitcoin Core.

• ● LND #9801 adds a new --no-disconnect-on-pong-failure option, which controls whether a peer is disconnected if a pong response is late or mismatched. This option is set to false by default, preserving the current behavior of LND disconnecting from a peer on a pong message failure (see Newsletter #275); otherwise, LND would only log the event. The PR refactors the ping watchdog to continue its loop when disconnection is suppressed.

Want more?

For more discussion about the topics mentioned in this newsletter, join us for the weekly Bitcoin Optech Recap on Riverside.fm at 16:30 UTC on May 27. The discussion is also recorded and will be available from our podcasts page.