Lightning Specification Meeting 2024/12/16

[t-bast]

The meeting will take place on Monday 2024/12/16 at 7pm UTC (5:30am Adelaide time) on Libera Chat IRC #lightning-dev. It is open to the public.

A video link is available for higher bandwidth communication: https://meet.jit.si/Lightning-Spec-Meeting

Recently Updated Proposals / Seeking Review

This section contains changes that have been opened or updated recently and need feedback from the meeting participants.

• Simplified mutual close option_simple_close (features 60/61) #1205
• Peer storage backup Peer storage for nodes to distribute small encrypted blobs. #1110
• Dual funding reconnect commit_sig retransmission Do not unnecessarily retransmit commitment_signed in dual funding #1214
• Taproot extension-bolt: simple taproot channels (feature 80/81) #995
• Taproot gossip extension-bolt: taproot gossip (features 32/33) #1059
• Trampoline routing Trampoline Routing (2021 edition) (Feature 56/57) #829 and Trampoline onion format (Feature 56/57) #836
• Bolt 12 contacts: blip-0042: Bolt 12 Contacts blips#42
• Splicing Channel Splicing (feature 62/63) #1160
• Dynamic Commitments Extension/dynamic commitments #1117
• Liquidity ads Extensible Liquidity Ads #1153
• Channel jamming draft: HTLC Endorsement to Mitigate Channel Jamming #1071
• Async payments Support async payments in BOLT 12 #1149
• Clarify channel_reestablish requirements Clarify channel_reestablish requirements #1049 or Rework channel_reestablish requirements #1051

Stale Proposals

This section contains pending changes that may not need feedback from the meeting participants, unless someone explicitly asks for it during the meeting. These changes are usually waiting for implementation work to happen to drive more feedback.

• Inbound fees Inbound routing fees blips#18 and Add a bLIP for backwards-compatible inbound fees blips#22

Waiting for interop

This section contains changes that have been conceptually ACKed and are waiting for at least two implementations to fully interoperate.
They most likely don't need to be covered during the meeting, unless someone asks for updates.

• Zero reserve Add option_zero_reserve (FEATURE 64/65) #1140 (follow-up on bolt2: relax channel_reserve_satoshis requirements #1133 to include a feature bit)
• Attributable errors Attributable errors (feature 36/37) #1044
• Don't force close until error is received after channel_reestablish Nodes shouldn't publish their commitment when receiving outdated channel_reestablish #934

Long Term Updates

This section contains long-term changes that need review, but require a substantial implementation effort.

• Simplified commitment Feature 106/107: option_simplified_update. #867
• lnprototest (https://github.com/rustyrussell/lnprototest)

[t-bast]

option_simple_close:

• can we re-design this to avoid needing a state machine at all?
• do we really want to be able to change our script after already signing a mutual close with a different script? that looks useless and dropping this would make the protocol much simpler

peer_storage:

• should be ready to merge, cross-compat tested between eclair and cln
• @TheBlueMatt will finalize some comments directly on the PR
• @adi2011 is working on LDK implementation and will decide whether to merge the spec now or wait for this implementation to make progress

dual_funding signature retransmission:

• since this only affects nodes who disconnect in the middle of a signature, it shouldn't happen on server nodes, so probably fine to make this change without coordinating releases between eclair and cln?
• needs a sign-off from @ddustin or @niftynei

trampoline / async payments:

• in-progress, looking good

[t-bast]

Note that we will skip the next spec meeting (december 30th), see you all in January!