Ninjastic
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Re: About the "Unknown block versions being mined!" warning
by
junan1
on 22/07/2017, 03:12:04 UTC
Quote from: tspacepilot on July 21, 2017, 07:03:49 PM
Quote from: xbiv2 on July 21, 2017, 05:48:15 PM
Fake news

https://blockchain.info/charts/bip-9-segwit

I guess the confusion here comes from the fact that you can signal BIP9 without signaling SegWit.   BIP9 signals on bit 4 and we definitely have like 80ish% of blocks in the last day or so signaling on bit 4.   SegWit readiness is signaled on bit 1 and I think that's what bc.i is tracking there.  As far as I know, in a couple hundred more blocks, the miners who signaled BIP9 are supposed to start rejecting blocks that don't signal segwit on bit 1.  We'll have to see whether all the folks who signaled BIP9 start putting bit1 and whether or not those who signaled BIP9 (bit4) actually do start orphaning blocks that don't signal bit1.

Disclaimer: this topic is confusing, I may be wrong.
 

  • BIP 9 ("version bits") is a standard for proposing Bitcoin upgrades or "deployments".  Code for this is included in Bitcoin Core.
  • BIP 141, together with BIP 143 and BIP 147, ("SegWit") is a deployment which follows the BIP 9 standard.  Code for this is included in Bitcoin Core.
  • BIP 91 ("SegSignal") is a deployment which uses the BIP 9 machinery while not strictly following the standard.  Code for this is not included in Bitcoin Core but is included in a fork of Bitcoin Core called "btc1".

By modifying the version field in the block header, miners can "signal" their support for any combination of deployments.  Bit 1 of the version field corresponds to SegWit and bit 4 corresponds to SegSignal.

https://blockchain.info/charts/bip-9-segwit charts the signalling of SegWit (bit 1) where each datapoint is in fact the average signalling rate of the prior 2016 blocks (~ 2 weeks).  However, as you rightly observe, there has been a recent increase in SegWit signalling.  Of the last 144 blocks (~ 1 day), 131 have signaled for SegWit (~ 91%).  If the 2016-block moving average chart is at 95% or higher at a difficulty change then SegWit will "lock in".

SegSignal is already locked in and all nodes following SegSignal will consider invalid any blocks at height 477120 or greater (~ 2017-07-23, 8:00am UTC) (edit) which do not signal SegWit.  Note again that Bitcoin Core does not include code for this deployment (hence the warnings) and so Bitcoin Core nodes will not reject blocks as SegSignal requires.