28

SegWit2x is a combination of both SegWit and a 2MB hardfork (to activate three months after SegWit). SegWit2x uses a different 'bit' for signaling (bit 4 instead of bit 1) than SegWit. SegWit (BIP141) is not activated at the moment because it requires 95% of the mining hashrate, and not enough miners support SegWit at the moment, because some miners want ...


8

Blocks signalling for the SegWit2x, i.e. the New York Agreement segwit activation (BIP91), are setting bit4. This shows up as a '1' in the second to last position of the version field. Blocks signalling readiness for BIP141, i.e. regular segwit activation, do so on bit1 which shows up as '2' in the last position of the version field. It is also possible to ...


6

Bitcoin Core is a specific implementation of the Bitcoin protocol, specifically the one in the Bitcoin GitHub Repository. It is the evolved version of the original client Satoshi wrote, in C++. It is also the reference implementation of Bitcoin. But Bitcoin Core is not the only Bitcoin node software, there are others written in other programming languages ...


5

Technically, the UASF that will go live on August 1st isn't a hardfork (see What is the User Activated Softfork (UASF) proposal? How do its risks compare to hardforks?), but it may have still have a chainsplit. When there is lack of consensus about the rules in the bitcoin network, there may be multiple blockchains, one blockchain following one set of ...


5

Will there be a hard-fork between B2X and BTC? Yes, most likely, although it's hard to know for sure. There seems to be enough people who want the 2x fork that it will happen, and there definitely are people who will continue running Bitcoin Core (which is the form of the bitcoin protocol that will stay with the current block size), which will create two ...


4

Nobody can determine the date for that event. SegWit, like every soft fork, requires a majority of miners to enforce the new rules in addition to economically relevant nodes. The initial BIP that proposes segWit, BIP 141, requires 95% of miners to signal they are ready for 2 weeks, before starting to enforce the new rules. This threshold is set so that at ...


4

It looks like it is actually periods of 336 blocks instead of a rolling window. It is like what BIP 9 specifies, but uses 336 blocks as the window and 269 blocks as the threshold. The windows begin when a block's height is a multiple of 336.


4

Yes, absolutely. Every output can independently be a normal or SegWit output (when using P2SH-embedded SegWit, you can't even tell until it is being spent). Every input can independently spend a normal output or SegWit output. When a transaction has at least 1 SegWit input it's called a SegWit transaction. When not all inputs are SegWit inputs, the ...


4

Since 2x has decided not to implement replay protection, transactions will be indeed compatible to both chains. If a transactions is simply broadcast to the other chain, it will enter the mempools there as well and may eventually get confirmed. This doesn't mean that one is completely helpless though. Here are some methods of making transactions valid only ...


3

Segregated Witness (segwit) is a solution which redefines how the maximum block size is calculated (now called block weight) and creates new output types. These segwit output types are given a discount (compared to non-segwit output types) with the new maximum size calculation when they are spent. This means that a block will be able to have more ...


3

Yes, that is certainly possible. BIP 143 has examples of such transactions. Transactions that spend from both segwit outputs and non-segwit outputs are still vulnerable to transaction malleability.


3

You can see that information here (SegWit2x is BIP91): https://www.xbt.eu/


3

I feel that the existing answers here fail to highlight that while (the collection of) miners have the authority to select the order of transactions, and impose additional validity rules, they do not have the authority to determine what the rules are. Segwit2X (in my understanding, there seem to be multiple ideas out there) seems to be a combination of a ...


3

segwit2x temporarily had an opt-in replay protection, but chose to remove it. it is intentional, as part of their strategy to make only one fork survive.


3

If I can choose between Bitcoin Core, Bitcoin ABC, Bitcoin XT, and Bitcoin Classic None of these software support Segwit2x. Currently your only choice of Full node software for Segwit2x is btc1.


3

All transactions would be replayable on both chains even after one was confirmed in a block on one chain, because since both chains start with the same UTXO set, the transactions spending those UTXOs are valid on both chains. The only exception is coins mined on each chain after the fork, because those coins will not be valid on the other chain. So that is ...


3

Key proponents of the New York Agreement have rescinded their support after large parts of the community opposed their initiative for months. Theoretically, a miner could still activate the fork unilaterally, but the expected value of the Segwit2x network dropped significantly with the exit of said key proponents.


3

Though its major proponents have called it off, there's a miner with an unknown (likely less than 10%) amount of hash power vowing to continue: https://cointelegraph.com/news/segwit-death-challenge-bitpico-vows-to-fork-as-bitcoincom-goes-100-bitcoin-cash You can monitor miners who are signaling for Segwit2x by looking at the coinbase of blocks here: https:/...


3

Here's an official announcement of the fork having taken place. According to the official website the fork is planned for block 501451 which has indeed occurred about 8 hours ago. The stats of their mining pool don't look to promising though, but it might be too early to tell. Also keep an eye out on their subreddit and other social media.


3

You are mistaking virtual size that got introduced with SEGWIT with the legacy size. 166 bytes is the virtual size. 248 bytes is the legacy one. Unfortunately, Blockchain.info shows only the legacy size. You can check your transaction with smartbit to get the VSize. You can also check this awesome article about SEGWIT fees calculation


2

No, all clients will be compatible until the HF and will mine one chain. If SegWit2x reaches 80% support during a 336 block signaling period, it means that the SegWit softfork locks in and will activate another 336 blocks later on all SegWit2x clients. Those clients will then, upon SegWit activating, automatically turn on bit1 signaling to assist the Core ...


2

As you can see from an answer given by a Trezor's staff member in this reddit post on 5th October 2017: We will do an official communication once it is clear what Segwit2x is and what is not. Currently, there are some changes in the Segwit2x queue which might or might not be accepted and this can change significantly what steps would need to be done. ...


2

August 1st has nothing to do with BIP 91, nor will segwit become active on August 1st due to either of BIP 148 or BIP 91. The current projected date for segwit to become active (assuming that BIP 91 is enforced) is August 24th. The segwit2x hard fork to 8 MB block weight is currently implemented as occurring 12960 blocks following the activation of segwit. ...


2

From following most of what has been going on in the btc1 repository, it is S2x's express plan to take along SPV wallets with their hard fork. Therefore, they are limiting wipeout protection to anything that doesn't break SPV wallet compatibility. Most notably they don't plan on using the proposed hardfork bit. I believe they are going to require a block ...


2

Your coins are safe on Trezor, you don't need to run full node for coins unless you want to help mine. If you want to access Segwit2X coin or any other BTC forked coins (in future) asap after the fork, then you should transfer your BTC coin to a lite client and get the private key of that wallet. Or else, you can wait until Trezor supports Segwit2X coin, ...


2

The minority of miners that do not support BIP91 (and by extension BIP141), could start rejecting blocks of those who are signaling BIP141, thereby creating a different chain. Is that a possibility both in theory and in practice? Yes that is possible, but unlikely. Since BIP 91 has a majority of the hashrate, I think it is unlikely that there will be a ...


2

No, it will not be easier. The "difficulty" of mining is determined by the difficulty (the value). The difficulty only adjust itself every 2016 blocks, so when the Segwit2x fork happens, the difficulty will not adjust until 1152 after the fork happens. So the difficulty will not change at the time of the fork for either chain (barring any difficulty ...


2

It is referenced relatively, namely by using the parameter BIP102HeightDelta. The hardfork is 3 months after the block that Segwit was actived and the number of blocks after is equal to 90(days)*144(blocks/day)(https://github.com/btc1/bitcoin/blob/385cbc994f35d36cefdab8c1c00ebfaceb55cfc6/src/chainparams.cpp#L78) Try to look for that parameter. It will ...


2

First of all, Segwit and Segwit2x are two different things. Segwit has already activated, Segwit2x has not. Please do not conflate the two. https://coin.dance/poli and http://segwit.party/nya/ list the positions of various companies and project's on Segwit2x although they are not always accurate or clear.


2

It is impossible for the receiver of a transaction to prevent transaction replay of the transaction. They cannot do anything to that transaction to make it unreplayable. However it is likely that Coinbase will credit both your Bitcoin and Segwit2x if a transaction is replayed. This is because they should be operating nodes for Bitcoin and nodes for Segwit2x ...


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