Three of China 's biggest mining pools – F2Pool, BTCChina Pool and Huobi Pool – maintain that the Bitcoin Core development team should strive for consensus, and will therefore not support a switch to Bitcoin XT. Given Core developer Gavin Andresen's latest proposal and the current hash-rate distribution on the Bitcoin network, a network wide shift from Bitcoin Core to Bitcoin XT to allow bigger blocks seems infeasible, for now.

Lacking consensus among Core developers to raise the block size limit, Andresen has recently shifted his efforts to Mike Hearn's Bitcoin Core fork, Bitcoin XT. In a newly released proposal, Andresen schedules to raise the block size limit on Bitcoin XT from 1 to 8 MB by 2016, after which it should double every other year. Before the change would go into effect, however, 750 of 1,000 consecutive mined blocks would need to include a message by the miner in approval of the change.

Andresen's proposal has been received relatively well by the Chinese mining pool operators, who themselves suggested a raise to 8 MB last week. Despite that, however, the proposal seems unlikely to be accepted as part of a unilateral hard fork through Bitcoin XT for now.

When asked by Cointelegraph, F2Pool, BTCChina and Huobi Pool – accounting for over 30% of hash-rate - have all indicated not to support a controversial shift from Bitcoin Core to Bitcoin XT.

Instead of a hard fork to Bitcoin XT in order to allow for bigger blocks, the Chinese mining pools suggest that Andresen continues to seek consensus among other Core developers. This way, a proposal to allow for bigger blocks could be implemented in the main Bitcoin client, without risking a split in Bitcoin's blockchain.

F2Pool, which is currently the biggest mining pool on the Bitcoin network with about twenty percent of total hashing power, has made it very clear that a switch to Bitcoin XT is not an option.

Speaking to Cointelegraph, F2Pool admin Wang Chun said:

“We will wait and see what other core developers think of Gavin's proposal. But we will certainly not switch to the altcoin called 'Bitcoin' XT. It could set a very bad precedent if we do that. No matter who you are, you cannot make a new coin and declare it is 'Bitcoin' simply because you do not agree with other core developers.”

BTCChina, which runs one of the biggest Chinese exchanges and accounts for some ten percent of network hash-rate, has previously indicated not to switch to Bitcoin XT either. And while the mining pool did express to like Andresen's proposed patch, a hard fork without consensus is still considered too big of a risk.

BTCChina's director of engineering Mikael Wang told Cointelegraph:

“We think Gavin's proposal is a well-balanced solution that we all can stand behind and support. The initial 8 megabyte block size increase was also the agreed number amongst all mining operators in China. BTCChina Pool will unfortunately not be running Bitcoin XT due to its experimental nature, but we are looking forward to see this patch merged into Bitcoin Core.”

Another of the “big three” Chinese exchanges, Huobi, which also runs its own mining pool Huobi Pool, called for cooperation among Core developers as well.

CEO of Huobi's mining project Digcoin, Evan Mo, emphasized that the Core developers need to restore their collaborative process in order to come to a consensus on Bitcoin scalability issues.

“We would like to see full communication among each party, even if it will arouse some argument and controversy,” Mo told Cointelegraph. “As we all know, the best results always come out through argument. As soon as the final solution is compromised and agreed by everyone, we will support and help upgrade.”

Additionally, Mo emphasized that a hard fork to raise the block size should be released only with extreme care. Therefore, an elaborate testing period will be required by Huobi before any change can be made in the first place. Mo concluded:

“After the final proposal, there should be about three months for testing, first on bitcoin test-net, then gradually moving to main-net. Since the mining pools and exchanges have very high safety and stability demand, we may have to experience a quite long testing phase, but it will be done within the deadline that everyone has agreed.”

Update July 7: AntPool, accounting for some 20% of hashing power on the Bitcoin network, sent us the following response:

"We like the idea of increasing the maximum block size, but if Bitcoin XT is too contentious, we also don't want the community to be divided. Doubling the block size every two years may be too arbitrary, we'd like to see the block size grow according to the real needs of the network."