The Frontier

Stratum v2's mining IPC interface uses Cap'n Proto over a Unix socket for efficiency, replacing JSON-based RPC for large data like block templates.

Shores says IPC was designed for splitting Bitcoin Core's node, wallet, and GUI processes, not originally for mining. It can serve indexers or Electrum servers.

Bitcoin Core avoids speaking Stratum v2 directly to reduce code complexity and network port risks. A sidecar app translates between IPC and the protocol.

PR 34020 adds two IPC methods to fetch transactions by TXID or witness ID. This lets a Stratum v2 job declarator reconstruct a block from the node's mempool.

Lucas's fountain code research proposes prune nodes store 'droplets' of block data to assist IBD. Murch notes concerns: slower sync, fingerprinting risk, adversarial 'murky nodes.'

Shores points to 21,000 nodes serving the full blockchain. He argues BitTorrent or Amazon could supply data if header validation exists, making fountain codes premature.

Bitcoin Core 31.1 fixes a bug where private broadcast could fall back to clearnet if V2 transport fails. It now retries V1 transport while retaining the proxy.

A UTXO database flush every hour caused excessive disk churn via LevelDB compaction. Core 31.1 reduces compaction frequency, backported to 30.3 and 29.4.

Core 31.1 also includes wallet migration fixes and intentional background compaction to manage disk I/O predictably.

LND 20.2 beta fixes a DNS fallback panic during peer discovery by validating record types, not assuming SRV. It also patches an HTLC forward interceptor issue.

Bitcoin Core PR 32489 adds an Export Watch Only Wallet RPC, exporting public descriptors and metadata. It simplifies multisig tutorials, eliminating manual bash scripts.

PR 32606 updates compact block relay: Bitcoin Core ignores compact block messages from peers that didn't negotiate support, aren't high-bandwidth, or run blocks-only mode.

Murch explains high-bandwidth peers send compact blocks unannounced, speeding propagation. Blocks-only nodes reject them because they lack a mempool for reconstruction.

Malicious compact block announcements could probe a node's mempool, especially for blocks-only nodes. The fix reduces this attack surface.

Core Lightning PRs 9104 and 9292 implement experimental Simple Close Option, a cooperative close protocol where peers independently broadcast signed closing transactions.

PR 9292 fixes an edge case where Core Lightning could accept then reject an uneconomical OP_RETURN output, preventing a forced close.

Eclair now fails incoming HTLCs with CLTV expires beyond 2016 blocks to prevent resource consumption, mirroring its existing rule for outgoing HTLCs.

LND's PR adds invoice request message support for Bolt 12 offers, building on prior groundwork. Full signature verification and offer checking remain for future PRs.