This week’s newsletter relays the announcement of a service bit being used for testing Utreexo, links to several new software releases and release candidates, and describes a merged Bitcoin Core pull request.


  • Service bit for Utreexo: Calvin Kim posted to the Bitcoin-Dev mailing list that software currently designed for experimentation on signet and testnet will be using P2P protocol service bit 24. The experimental software provides support for Utreexo, a protocol for allowing full verification of transactions by nodes that don’t store a copy of the UTXO set, saving up to 5 GB of disk space compared to a modern Bitcoin Core full node (without any reduction in security). A Utreexo node needs to receive extra data when it receives an unconfirmed transaction (or a block full of confirmed transactions), so the service bit will help a node find peers capable of providing the extra data.

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.

  • Core Lightning v23.02.2 is a maintenance release of this LN node software. It reverts a change to the pay RPC that cause problems for other software and includes several other changes.

  • Libsecp256k1 0.3.0 of this cryptographic library. It includes an API change which breaks ABI compatibility.

  • LND v0.16.0-beta.rc3 is a release candidate for a new major version of this popular LN implementation.

Notable code and documentation changes

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

  • Bitcoin Core #25740 allows a node using assumeUTXO to verify all blocks and transactions on the best block chain until reaching the block where the assumeUTXO state claimed it was generated, building a UTXO set (chainstate) as of that block. If that chainstate is equal to the assumeUTXO state downloaded when the node was first started, then the state is fully validated. The node has validated every block on the best block chain, the same as any other full node, it has just validated them in a different order than a standard node. The special chainstate used to perform the verification of older blocks is deleted the next time the node starts, freeing disk space. Other parts of the assumeUTXO project still need to be merged before it will be usable.