For the first time, bitcoin miners have been able to signal support for Segregated Witness this past week. Developed as a soft fork, the proposed centerpiece of Bitcoin Core’s scalability roadmap requires 95 percent of all blocks within a single two week difficulty period to signal readiness for the change. If the threshold is reached, the solution is activated two weeks later, realizing an effective block size limit increase, a malleability fix and more.

Of all mining pools accounting for at least one percent of hash power on the network, four have been signaling support for Segregated Witness so far, together accounting for about 26 percent of all newly mined blocks.

Here is a brief overview.

AntPool (~19 percent hash power)

AntPool, the main mining arm of China-based ASIC-producer Bitmain, has not been signaling support for Segregated Witness so far.

At the “Bitcoin Roundtable” in Hong Kong last February, Bitmain and AntPool representatives signed a letter supporting Segregated Witness, in return for a hard fork proposal to increase the block size limit from the Bitcoin Core developers present at the meeting. This hard fork proposal was scheduled to be presented within three months after the release of Segregated Witness — originally set for April. Due to a delay of Segregated Witness, however, the developers technically have until late next January to present the proposal.

Much has happened since the Hong Kong meeting, however, and interpretations of the agreement vary. Several of the signatories — including Bitmain CEO Jihan Wu and several Bitcoin Core developers — (seemingly) accused others of not upholding their part of the deal. Whether the developers will present a finished proposal before the end of January is uncertain.

Speaking to Bitcoin Magazine in May of this year, Wu said his pool will not support Segregated Witness unless and until Bitcoin Core implements a block size hard fork. This currently seems unlikely to happen any time soon.

F2Pool (~14 percent hash power)

The operator of the Chinese mining pool F2Pool, Wang Chun, signed onto the Hong Kong Roundtable consensus as well. Though he did not comment on the status of the agreement, Chun told Bitcoin Magazine that he is currently experiencing technical difficulties keeping him from signaling support.

“Since our system cannot build C++11, I would like put this on hold for a while, until we can get our new servers online up and running,” Chun said. “Next spring, maybe.”

BTCC (~11 percent hash power) signals support

China-based Bitcoin exchange, wallet service and mining pool BTCC signed the Hong Kong Roundtable letter. The company is one of the most outspoken proponents of Segregated Witness and is currently the biggest mining pool signaling support.

Speaking to CoinTelegraph last week, BTCC COO Samson Mow explained:

“SegWit is great for Bitcoin. It brings more transaction throughput, fixes malleability, defrags the UTXO set, makes hardware wallets more secure and most importantly, it enables lightning, which will bring instant low cost Bitcoin transactions to the world. The team at BTCC have been working hard at making our exchange and mining pool services SegWit-ready.”

BW Pool (~10 percent hash power)

BW Pool, China’s fourth biggest mining pool and another signatory of the Hong Kong Roundtable letter, is currently not signaling support for Segregated Witness.

Earlier this week, the mining pool did send out a tweet stating: “Mining Pools Should Remain Neutral.” This is in agreement with Slush Pool’s policy to let individual miners connected to the pool decide whether they want to signal support in blocks they find, rather than having the pool decide for them.

In response to a query from Bitcoin Magazine, BW Pool angel investor, Chandler Guo, confirmed the pool will let individual miners decide. Guo did not reveal further specifics, however, such as activation dates or potential default settings.

BitFury (~7 percent hash power) signals support

BitFury, a full-service Blockchain technology company and mining pool with roots in the Republic of Georgia, is currently the second largest pool signaling support for Segregated Witness.

Representatives from BitFury also signed the Hong Kong Roundtable letter. And commenting on the block size issue at a conference in London, BitFury CEO Valery Vavilov stated the “block size should be increased, but in a smart way,” adding that “the solution which was deployed is pretty good: Segregated Witness.”

ViaBTC (~6 percent hash power)

Of all mining pools, the relatively new Chinese mining pool ViaBTC is perhaps the strongest opponent of the Segregated Witness soft fork. In an interview with Bitcoin Magazine published last week, ViaBTC CEO Haipo Yang explained he will reject the proposed soft fork in favor of a block size limit increase hard fork.

“My goal is not really to block Segregated Witness in and of itself, but to work towards a Bitcoin version I think is better,” Yang said.

HaoBTC (~6 percent hash power)

Representatives from HaoBTC, the Chinese exchange, wallet service and mining pool, signed onto the Hong Kong Roundtable consensus.

In June of this year, the company published an open letter urging the Bitcoin Core developers present in Hong Kong to uphold their part of the deal — and asking for clarity. While the letter was quickly unpublished, the original content suggests HaoBTC was not fully happy with the (lack of) progress on the hard fork proposal. (Additionally, the original letter is said to have included positive remarks concerning Segregated Witness.)

HaoBTC is currently not signaling support for Segregated Witness, however.

Slush Pool (~6 percent hash power) partially signals support

Prague-based Slush Pool, Bitcoin’s oldest mining pool, will let individual hashers decide whether or not to signal support for Segregated Witness.

In an article published on Bitcoin Magazine last week, pool operator Marek “Slush” Palatinus explained he wants to remove himself from the equation as a decision maker: “Satoshi’s idea was not to have a few entities control the network. As a mining pool we shouldn’t rule.”

Slush Pool will signal support for Segregated Witness by default, but users can opt out if they want. This solution isn’t quite ready yet at the moment, however. As a temporary solution, only users that “vote” in support of Bitcoin Core automatically vote for Segregated Witness.

BTC.com (~5 percent hash power)

BTC.com, a block explorer, wallet service, API-provider and open source mining pool owned by Bitmain, is currently not signaling support for Segregated Witness.

Speaking to Bitcoin Magazine, BTC.com’s mining pool operator, Kevin Pan, indicated that, in the short term, it will not signal support for Segregated Witness but will instead await further community consensus. Like AntPool, BTC.com’s decision will most likely also depend on Bitmain’s preference.

GBMiners (~3 percent hash power)

India-based GBMiners, another relatively new mining pool, is not signaling support for Segregated Witness. In an interview with CoinJournal, the mining pool did indicate that it is in favor of the Bitcoin Core fork Bitcoin Unlimited, which has no plans to support Segregated Witness.

Update: In reply to a query on Facebook on October 20, GBMiners representative Sanjay Goswami indicated (mirror) that his pool would would signal support for Segregated Witness.

Bitclub Network (~3 percent hash power) signals support

Bitclub Network is the fourth largest mining pool currently signaling support for Segregated Witness. Not much else is known about this pool.

1Hash (~3 percent hash power)

Chinese mining pool 1Hash is currently not signaling support for Segregated Witness. Not much else is known about this pool.

Bitcoin.com (~2 percent hash power)

The new Bitcoin.com mining pool, operated by well-known Bitcoin angel investor and entrepreneur, Roger Ver, is currently not signaling support for Segregated Witness. Ver told Bitcoin Magazine that his pool “isn’t actively supporting or blocking SegWit,” but will only support Segregated Witness if and when it is clear to him there is community consensus for the soft fork.

Ver also addressed what he considers to be the lack of opportunity for uncontested dialogue about the soft fork within popular Bitcoin forums r/bitcoin and Bitcointalk:

“The problem with all the censorship that’s been going on is that no one knows what the community consensus actually is.”

Kano CK Pool (~2 percent hash power)

Kano CK Pool is not signaling support for Segregated Witness. In a comment on Bitcointalk, Kano CKPool operator “kano” recently indicated the pool will keep mining standard Bitcoin blocks; blocks that do not support changes to the protocol.

“No random attempts at changing BTC … and also no SegWit indicators,” kano said when asked which software the pool supports. “So I guess that means ‘core’ without SegWit voting.”

Bitcoin Magazine reached out to (representatives from) AntPool, BTCC, BitFury, HaoBTC, Bitclub Network, GBMiners, 1Hash and Kano CK Pool, but received no response at time of publication.

This article has been updated with information regarding GBMiners.