IRC meeting summary for 2016-03-17


Main topics

  • Scheduling the first BIP 9 sort fork for BIPs 68, 112, 113
  • Features for 0.12.1 besides BIP 9
  • State of segregated witness

Scheduling the first BIP 9 sort fork for BIPs 68, 112, 113


VersionBits BIP9 allows using the block header version field as a bit array so that miners can indicate readiness for up to 29 soft forks simultaneously. According to the current code and proposal, a miner that isn’t signaling readiness for any soft forks will create ‘version 4 blocks’, that is blocks with the same version as used to trigger and enforce the BIP65 CLTV soft fork.

meeting comments

Everyone seems happy with PR #7575 (merged shortly after the meeting).
Once there’s a decision on the start date and bit number, it should be announced on the mailinglist so other implementations can implement it as well.
Btcdrak and Morcos will have the backports for 0.12 & 0.11 ready.
The BIP9 BIP text is up to date, it would be a good idea to update BIP’s 68, 112 and 113 with the soft fork info as well.

meeting conclusion

  • Merge #7575
  • Review #7648
  • Start date for deployment based on BIP9 is May 1st, the bit number is 0.
  • btcdrak will update the deployment section of BIP texts 68, 112 and 113 with the new soft fork info.

Features for 0.12.1 besides BIP 9

meeting comments

Jonasschnelli has been working on GUI warning capabilities (PR #7579), people are fine with postponing it to 12.2 in order to focus on the softfork for 12.1 Morcos would like to add his and jonasschnelli’s PR’s #7715(“Fix calculation of balances and available coins”) and #7707 (“UI support for abandoned transactions”) which support and deal with abandoned transactions in order to respend outputs that had a too low fee.

Wumpus notes he likes to avoid bringing a lot of new features alongside a softfork. Right now the alert system for checking if you’re on a bad chain has a lot of false-positives, there’s a sense of urgency to either fix it or disable them since maintaining the current state will make people ignore the warnings. A fix has been made by dgenr8 (PR #7568)

meeting conclusion

  • Review #7568 (“Corrections to bad-chain alert triggering”) & #7715
  • #7707 RPC-only (commit 42e945d79fd54ab11ad48978910b42d10c1c7cf8), which is 1 line of code.

State of segregated witness


Several developers are working on a soft fork to introduce segregated witness onto Bitcoin mainnet, with initial testing being performed on a special testnet. Segregated witness allows transaction signature data to be stored outside of the data hashed to produce transaction identifiers, removing all known forms of third-party malleability, allowing full nodes to compile the current UTXO set without downloading all signatures, and laying the groundwork for fraud proofs that can allow lightweight (SPV) clients to help enforce more of the consensus rules. The segwit soft fork also allows miners to substitute 1 byte of block space with 4 bytes of segwit data, increasing transaction capacity for wallets that use segwit.

meeting comments

Sipa is working on the post-fork upgrade problem in the current segnet code, after that he’ll do a new segnet that includes the versionbit logic.
He’s aiming to have it ready before the 0.13 release.

Comic relief

sipa:       I'm glad bip9 seems final  
btcdrak:    sipa: party at your house. we'll bring the beers.  
jonasschnelli:    btcdrak finally de-anonymizes at the party.  
btcdrak:    haha  
sipa:       jonasschnelli: that's why you bring a drink mixer


IRC nick Name/Nym
jtimon Jorge Timon
btcdrak BtcDrak
gmaxwell Gregory Maxwell
jonasschnelli Jonas Schnelli
morcos Alex Morcos
sdaftuar Suhas Daftuar
sipa Pieter Wuille
wumpus Wladimir van der Laan


This summary was compiled without input from any of the participants in the discussion, so any errors are the fault of the summary author and not the discussion participants.