Highlights for Users

• This release candidate includes a downgrade tool! lightningd-downgrade will downgrade your database from v25.12 to v25.09 if something goes wrong
• New nodes will now be created with a BIP-39 12-word phrase as their root secret. BIP-39 12-word base functionality in lightning-hsmtool to support hsm_secret files.
• We solved the case of the missing_utxo bug!!
• We received great feedback about xpay and adjusted accordingly: which will no longer try to send too many HTLCs through unknown channels (6, as that is Phoenix's limit) unless it has no choice, we've fixed a clash with simultaneous payments via routehints and blinded paths and asked xpay to wait if it suspects a payment failure is due to a height disagreement with the final node.
• Added askrene-bias-node: an RPC command to set a bias on node's outgoing or incoming channels.
• Use the new networkevents subsystem to access information about peers: ping times and connection times.
• We've configured an experimental-lsps-client and experimental-lsps2-service support for LSPS level 2 specification.

Highlights for Developers

• Multiple significant speedups for large nodes have been added to lightningd, especially preventing "freezes" under exceptionally high load and helping it to handle large numbers of command outputs gracefully.
• Postgres: significant speedup on read-only operations (e.g. 30% on empty SELECTs)

Protocol Updates

• We now re-transmit unseen funding transactions on startup, for more robustness.
• Stricter conformance to Bolt spec for splice commitments.