IRC meeting summary for 2015-11-26



Main topics

  • CLTV activation
  • BIP68/BIP112 implementation
  • Replace-by-fee

CLTV activation


CheckLockTimeVerify (CLTV) aka “how you thought nLockTime worked before you actually tried to use it” aka OP_HODL.

meeting comments

It’s plausible the CLTV softfork will activate within just a few weeks, as everyone but a few big miners have adopted it.
About 20% of the nodes currently run CLTV-supporting versions. The negative effect of not upgrading is a degraded validation (SPV).

meeting conclusion

Do a social media reminder to upgrade nodes to v0.11.2/v0.10.4

BIP68/BIP112 implementation


In short: BIP 68 changes the meaning of the sequence number field to a relative locktime. BIP 112 makes that field accessible to the bitcoin scripting system.

meeting comments

The BIP68 and BIP112 texts have been updated to match the implementations.
There’s been a call and discussion to rename CHECKSEQUENCEVERIFY on the mailinglist.
btcdrak wants both pull-requests to be merged soon, others feel more hesitant as people seem to only recently started looking at it seriously.

meeting conclusion

Merge updated BIP-texts



Currently when a node sees a transaction that spends the same output it ignores it. With replace-by-fee it replaces the current transaction in the mempool if it has a higher fee.
This allows for things like spending “stuck” transactions, adding more recipients to a transaction in order to prevent chaining, etc.

Since there are people that accept 0-confirmation transactions and this would make it extremely easy to double spend them, this is made opt-in.
The sender can choose to opt-in to replace-by-fee by changing the nSequence field of all inputs.
This is a mempool policy for the upcoming 0.12 release.

There’s a good FAQ-ish post on reddit about it.

meeting comments

petertodd ran some tests with the mempool limiter turned way down and saw no issues.
It should be technically easy to merge first-seen-safe and full-unconditional as options if there’s people who want to write it.

meeting conclusion

test and ACK replace-by-fee (Has been merged meanwhile).


btcdrak         btcdrak  
petertodd       Peter Todd  
Luke-Jr         Luke Dashjr  
CodeShark       Eric Lombrozo  
sipa            Pieter Wuille  
jtimon          Jorge Timón  

Comic relief

19:17	btcdrak		wumpus: so no meeting today then?  
19:17	CodeShark	btcdrak: so no wumpus today then? :)  
19:17	petertodd	btcdrak: since when do you listen to authority? :P  

19:22	CodeShark	is there a quorum? or can we meet anyhow? :)  
19:22	petertodd	CodeShark: I'm in a mcdonalds right now, working on increasing my influence, as measured by mass...  
19:22	petertodd	CodeShark: so yes  

19:49	btcdrak		### 10 minutes left. are there any other topic suggestions?  
19:50	petertodd	btcdrak: rbf  
19:50	btcdrak		#topic RBF    
19:51	CodeShark	anyone have a topic that pays a higher fee? :)    
19:51	Luke-Jr		this fee is too low, I'm leaving early!     

19:24	btcdrak		#meetingstart  
19:24	btcdrak		#startmeeting  
19:24	lightningbot	Meeting started Thu Nov 26 19:24:40 2015 UTC. The chair is btcdrak. Information about MeetBot at

20:00	btcdrak		#endmeeting  
20:00	btcdrak		#meetingend  
20:00	btcdrak		oh ffs, not this problem again  
20:00	lightningbot	Meeting ended Thu Nov 26 20:00:24 2015 UTC. Information about MeetBot at . (v 0.1.4)


This summary was originally compiled by Stefan Gilis aka “G1lius” and posted to the bitcoin-discuss mailing list with the disclaimer, “Please bear in mind I’m not a developer so some things might be incorrect or plain wrong.” and placed copyright in the Public Domain.