About the "Unknown block versions being mined!" warning

[achow101]

If you are using Bitcoin Core and derivative software, then you may have noticed that there is now a warning that states:

Warning: Unknown block versions being mined! It's possible unknown rules are in effect

This warning will appear at the top of the Bitcoin Core GUI and reported in the errors or warnings field of the getinfo, getnetworkinfo, and getmininginfo RPC commands.

This warning is triggered when more than 50 of the last 100 blocks have a version number that Bitcoin Core does not expect. Currently that is being triggered by miners mining for BIP 91 (aka the first half of segwit2x). These miners are setting bit 4 of the block version field, and Bitcoin Core does not expect this to be set.

The version numbers that Bitcoin Core expects are 0x20000000 (536870912) and 0x20000002 (536870914). The unexpected version numbers currently are 0x20000012 (536870930) and 0x20000010 (536870928).

Currently this warning is benign as there is no fork and no new network rules have activated. Your coins are not at risk.

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[Mad7Scientist]

I'm glad the developers thought to put that warning in. So basically this means that we're getting SegWit2x, or at least the first phase of it since it's still 4 days away from July 21st when SegWit2x activates and that warning indicates that 50% or more of miners are SegWit2x which is enough to win the soft fork. I guess whether the hard fork stays or not remains to be seen.

[achow101]

I'm glad the developers thought to put that warning in. So basically this means that we're getting SegWit2x,

No, that is not a guarantee that we will be getting segwit2x.

or at least the first phase of it since it's still 4 days away from July 21st when SegWit2x activates

Segwit2x is not guaranteed to activate on July 21st. It is not activated via flag day, rather it is activated via miner signalling. July 21st is the day that those who signed the New York Agreement for Segwit2x are supposed to begin signalling and running segwit2x nodes. But that is not a guarantee that activation will happen that day nor is it a guarantee that everyone will actually do so.

and that warning indicates that 50% or more of miners are SegWit2x which is enough to win the soft fork.

No, that is completely incorrect. The threshold for BIP 91 (the first half of segwit2x) is 80%, not 50%. Secondly, a 100 block period is much too short to determine anything. It can be highly affected by variance and luck. You need to much longer timespan to determine how much support there actually is. Even the 336 block window for BIP 91 is very short and could be affected by variance so there could actually be less than 80% hash rate support and BIP 91 would still activate.

[Mad7Scientist]

80% of exactly what must be present in the blockchain for SegWit2x to activate?

[achow101]

80% of exactly what must be present in the blockchain for SegWit2x to activate?

269 of the last 336 blocks (~80% of the last 336 blocks) must set bit 4 of the version number field in order for BIP 91 (first half of segwit2x) to activate.

[Icon]

well if segwit goes active will it work with our core 14.x version ? or are we screwed?

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[achow101]

well if segwit goes active will it work with our core 14.x version ? or are we screwed?

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Yes, it will work with Bitcoin Core 0.13.1+

[Mad7Scientist]

It shouldn't matter for non miners right?

[Icon]

O ok, well thought they were implementing a  different version of segwit, seeing i read core's version needed 95% signaling for it to go active, but segwit2x is doing it with ~ 80%? Anyways as long as its the same as core version shouldn't have any forks, i guess until they start the hard fork to 2mb block size right?


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[Icon]

It shouldn't matter for non miners right?

Only if you hold your own private keys to your coins.. If a website/smart phone does then it doesn't matter for non miners.

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[CreditM8]

Thanks for the warning. Haven't started mining just yet, but better to know than not.

[Amph]

so even in a remote case of an hard fork, which could be imminent, we just leave our coins there on core, and we should be safe from my understanding, as long as we don't move those coins right?

[freedomno1]

Thanks Achow for the clarification for those who are not keeping track of the forking issues, this would scare a few individuals since it has not been seen before even if they are running core and know the fork is coming how it impacts the nodes isn't really defined.

On a sidenote what versions of Bitcoin Core should a person utilize considered safest for segwit2x or does it matter as long as it ain't QT ^^.

[orio]

Hello

If I see that message in my Core wallet, is it safe to send coins somewhere now ?

[achow101]

O ok, well thought they were implementing a  different version of segwit, seeing i read core's version needed 95% signaling for it to go active, but segwit2x is doing it with ~ 80%?

Segwit2x is using BIP 91. BIP 91 specifies that 269 of the last 336 blocks (~80% of the last 336 blocks) must signal for BIP 91 on bit 4. Once there is enough signalling, it will be locked in for a short grace period of 336 blocks. Then it will activate. Once BIP 91 activates, all blocks must signal for segwit on bit 1. This means that segwit will then activate via its original deployment on bit 1. Segwit2x is not actually activating a different segwit, they are activating something else which will force the activation of segwit.

Anyways as long as its the same as core version shouldn't have any forks, i guess until they start the hard fork to 2mb block size right?

There may be forks since 20% of the hash rate won't be support BIP 91 and thus will likely not be signalling bit 1 for segwit. With some luck and spy mining, forks could be made from miners extending a chain off of a block which does not signal bit 1. However Bitcoin Core will allow you to choose the chain to use (via the invalidateblock RPC command) and any of the forks will be valid to Core.

If BIP 91 activates successfully and everyone who claims they will enforce it actually enforces it, then there shouldn't be a fork.

so even in a remote case of an hard fork, which could be imminent, we just leave our coins there on core, and we should be safe from my understanding, as logn as we don't move those coins right?

Yes. Coins at rest are not at risk.

On a sidenote what versions of Bitcoin Core should a person utilize considered safest for segwit2x or does it matter as long as it ain't QT ^^.

Any recent version of Core should be fine, even ones that don't have segwit support.

If I see that message in my Core wallet, is it safe to send coins somewhere now ?

Yes. There currently is no fork, so you can safely send your coins.

[Minecache]

If you are using Bitcoin Core and derivative software, then you may have noticed that there is now a warning that states:

Warning: Unknown block versions being mined! It's possible unknown rules are in effect

This warning will appear at the top of the Bitcoin Core GUI and reported in the errors or warnings field of the getinfo, getnetworkinfo, and getmininginfo RPC commands.

This warning is triggered when more than 50 of the last 100 blocks have a version number that Bitcoin Core does not expect. Currently that is being triggered by miners mining for BIP 91 (aka the first half of segwit2x). These miners are setting bit 4 of the block version field, and Bitcoin Core does not expect this to be set.

The version numbers that Bitcoin Core expects are 0x20000000 (536870912) and 0x20000002 (536870914). The unexpected version numbers currently are 0x20000012 (536870930) and 0x20000010 (536870928).

Currently this warning is benign as there is no fork and no new network rules have activated. Your coins are not at risk.

Maybe you could pin this and lock the thread where the member is intentially fudding over this?

https://bitcointalk.org/index.php?topic=2027108.0

[J.Socal]

So what day should we stop buying or selling btc?And for how long?

[kano]

It seems a little bazaar that achow101 is complaining about an 80% acceptance for SegWit with BIP91
when MOST of Core is going for BIP148/BIP149 that requires NO signalling for SegWit at all - the 95% activation has long been discarded by MOST of Core.

https://en.bitcoin.it/wiki/Segwit_support

Hypocrites all over the place ...


So your now predicting the future also?
How did you manage to determine that "since 20% of the hash rate won't be support BIP 91"

...
There may be forks since 20% of the hash rate won't be support BIP 91 and thus will likely not be signalling bit 1 for segwit. With some luck and spy mining, forks could be made from miners extending a chain off of a block which does not signal bit 1. However Bitcoin Core will allow you to choose the chain to use (via the invalidateblock RPC command) and any of the forks will be valid to Core.
...

BIP91 is built off Bitcoin Core code - so even BIP91 will "allow you to choose the chain to use" since that function is old.

[JayJuanGee]

So what day should we stop buying or selling btc?And for how long?

I had been considering this too, and I thought that between about July 30 until mid to late August, but we have to continue to monitor whether it might be o.k. to continue with our trades and transfers.  I imagine that there are members who have much more solid understandings than me.

[Meuh6879]

It seems a little bazaar that achow101 is complaining about an 80% acceptance for SegWit with BIP91
when MOST of Core is going for BIP148/BIP149 that requires NO signalling for SegWit at all - the 95% activation has long been discarded by MOST of Core.

https://en.bitcoin.it/wiki/Segwit_support

Hypocrites all over the place ...


So your now predicting the future also?
How did you manage to determine that "since 20% of the hash rate won't be support BIP 91"

...
There may be forks since 20% of the hash rate won't be support BIP 91 and thus will likely not be signalling bit 1 for segwit. With some luck and spy mining, forks could be made from miners extending a chain off of a block which does not signal bit 1. However Bitcoin Core will allow you to choose the chain to use (via the invalidateblock RPC command) and any of the forks will be valid to Core.
...

BIP91 is built off Bitcoin Core code - so even BIP91 will "allow you to choose the chain to use" since that function is old.

Perfect Explanation.