Lightning Specification Meeting 2024/04/08

[Roasbeef]

The meeting will take place on Monday 2024/03/25 at 7pm UTC (5:30am Adelaide time) on Libera Chat IRC #lightning-dev. It is open to the public.

⚠️ Some countries are switching to DST in the coming weeks, be careful with the meeting time!

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.

• Spec clean-up Clean up: remove two unused features, assume four more #1092
• Simplified mutual close option_simple_close (features 60/61) #1096
• Liquidity ads option_will_fund: liquidity ads #878 Advertise liquidity ads rates #1145
• Allow sciddir_or_pubkey for every hop Compact representation for node id #1138
• Async payments Support async payments in BOLT 12 #1149
• Trampoline routing Trampoline Routing (2021 edition) (Feature 56/57) #829 and Trampoline onion format (Feature 56/57) #836
• Quiescence BOLT 2: quiescence protocol (feature 34/35) option_quiesce #869~
• Splicing Splice draft (feature 62/63) #863 vs Dynamic Commitments Extension/dynamic commitments #1117 vs Upgrade on reestablish BOLT 2: upgrade protocol on reestablish #868
• Taproot extension-bolt: simple taproot channels (feature 80/81) #995
• Taproot gossip extension-bolt: taproot gossip (features 32/33) #1059
• Peer storage backup Peer backup storage (feature 40/41/42/43) #881 or Peer storage for nodes to distribute small encrypted blobs. #1110
• Channel jamming draft: Staking Credentials token issuance/redemption #1043 draft: HTLC Endorsement to Mitigate Channel Jamming #1071 blip-0004: experimental endorsement signaling in update_add_htlc blips#27
• Offers Offers #798
• DNS-based offers Define a mechanism for looking up an offer from a user/domain pair #1136
• Attributable errors Attributable errors (feature 36/37) #1044
• 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)
• 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)

[Roasbeef]

feature bit clean up:

• moving back to optional for gossip queries
• PR to be updated
• some follow up for static remote keys re feature bits

rbf coop close:

• lnd to update with the lock time change, then start interop with eclair

liquidity ads:

• PR now updated, has the additional details in the body, needs review

trampoline:

• LDK moving forward with serialization and parsing support, moving now into API and beyond

stfu interop:

• doing interop testing w/ lnd and eclair -- revealed a bug in the lnd impl, currently fixing
• lnd working on putting up a draft of the resume message, to detail all the semantics around if the messages arrive out of time
  • how do you handle the complexity on sending resume, then something else happens, all those edge cases
  • similar-ish to what you'd already handle for random disconnect

splicing:

• dusty fleshing out his splicing DSL
• spec progress:
  • big TODO list of things working thru, 8-12 items to get through: Splice draft (feature 62/63) #863 (comment)
  • once those are through, then back to more interop to polish up the spec further

taproot & gossip:

• eclair working on interop
• lnd on holding pattern w gossip changes

peer back up:

• lnd progressing w/ implementation, almost complete

blinded paths:

• lnd on final PR, error handling items, hoping to land into 0.18 (next major release)
• interop:
  • lnd <-> CLN: max CLTV height seems to be wrong, issue made in the CLN tracker for

channel jamming:

• bLIP now ready for people to take a look at
• setting the bit now, questions of how many bytes should be allocated to the purpose

offers:

• scid pubkey is still there, now only for the introduction node
• LDK has PR to do parsing, then handling is up next

inbound fees:

• lnd merged in initial version, staged roll out, negative only (discounts to start with)

[jkczyz]

offers:

• scid pubkey is still there, now only for the introduction node
• LDK has PR to do parsing, then handling is up next

Small correction: the PR does parsing and handling, just not creation

[carlaKC]

Transcript: bitcointranscripts/bitcointranscripts#478