Lightning Specification Meeting 2025/06/16

[t-bast]

The meeting will take place on Monday 2025/06/16 at 8pm 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.

• [x] Gossip infinite loop #1256
• [x] Dual funding reconnect commit_sig retransmission #1214
• [x] Allow non-initiator to RBF dual-funded channels #1236
• [x] Assume option_channel_type #1232
• [x] Don't force close until error is received after channel_reestablish #934
• [x] Splicing #1160 #1268
• [x] Receiver-side random delays #1263
• [x] Attributable failures #1044
• [x] Taproot #995
• [ ] ~Taproot gossip #1059~
• [ ] ~Channel jamming #1071 #1218~
• [ ] ~Path queries #1259~
• [ ] ~Trampoline routing #829 and #836~
• [ ] ~Async payments #1149~
• [ ] ~BOLT 12 recurrence #1240~
• [ ] ~Bolt 12 contacts: https://github.com/lightning/blips/pull/42~
• [ ] ~Liquidity ads #1153~
• [ ] ~Dynamic Commitments #1117~
• [ ] ~0-fee commitments #1228~
• [ ] ~Moderation rules #1254~

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 https://github.com/lightning/blips/pull/18 and https://github.com/lightning/blips/pull/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 #1140 (follow-up on #1133 to include a feature bit)~

Long Term Updates

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

• [ ] ~Simplified commitment #867~
• [ ] ~lnprototest (https://github.com/rustyrussell/lnprototest)~
• [ ] ~Investigate QUIC transport #1257~

[ariard]

Moderation rules https://github.com/lightning/bolts/pull/1254

that one can be removed, unless someone wishes to grab it, but I doubt...

out for good of LN development, finished with the latest stuff that was still under my sleeves.

still recommend for CVE-2025-27586 to have the fixes integrated at the spec-level, though won’t do it.

i still think i owe a summit to the community, though i’ll estimate my balance sheet in order there.

[Roasbeef]

optional channel type required:

• eclair has merged in
• lnd has PR up for, should land in next major release

force close behavior for error message receive:

• bring up the old issue
• lnd still needs to look into effect on SCB flows

splicing:

• existing measure to reduce downtime for spliced channels
• right now spec says 12 blocks, wanting to increase 12 blocks, maybe 36 blocks or so
• situation where if the counter party waits longer, then may cause sync issues
• PR inc to update spec to a new value

receiver side delays:

• long tail of actual work here, fundamentally as a low latency onion network, vulnerable to timing+packet attacks
• spec recommendation to just do some sort of delay in general, more work to be done to look at params/techniques

attributable errors:

• only the multiplier encoding actually serves to constrain
• could just have it be a blob value, lets us ship the greater proposal w/o
• just need to pick the divisor now: something between 50-100 ms

taproot updates:

• lnd still to put up PR that switches over to use the new scripts along side a new top level feature bit
• also a shift to encode a pair of nonces
• retransmission:
  • if you owe a sig that they didn't get, then you need to re-sign with the same nonce