As Bitcoin XT failed to get universal acceptance, more bitcoin improvement proposals are voiced. While at the moment Bitcoin Classic seems to be the most popular, Gavin Andresen is ready to support other versions as well.

While Hearn’s proposal was rejected by the majority of bitcoin users, most industry leaders still feel the urge to increase the block size. Three alternative projects have been recently launched, according to Bitcoin Magazine.

Bitcoin Classic proposes to increase the block size limit to 2MB once 75% of bitcoin miners endorse the new format. Similarly to Bitcoin XT, it plans to create a hard fork but not instantly, giving bitcoin nodes time to adapt to the new version of bitcoin. Bitcoin Unlimited suggests to allow miners to manually increase the block size limit on their own nodes if they choose to. The third project, released by BitPay, is still in an experimental phase. It plans to create flexible block size limits that would adjust every 2016 blocks or two weeks, similar to the bitcoin mining difficulty.

Bitcoin Classic has been so far the most successful of proposals, receiving backing from large mining pools such as AntPool, BitFury and BWPool, as well as from Coinbase and OKCoin. Gavin Andresen, formerly one of the creators of Bitcoin XT, worked to improve the code of Bitcoin Classic. However, in his blog post he did not exclude the possibility he would work for Bitcoin Unlimited and other bitcoin implementations. According to him, “competition is good,” and “everything will work out fine, no matter what happens with the block limit.” Even if no quick solution is found, “bitcoin will survive… but adoption and growth might be set back a year or two.”

The block size limit debate dominated the whole of 2015. As the volume of bitcoin transactions in the world was growing, the 1MB block size limit established by Satoshi Nakamoto seemed insufficient. In June 2015 Gavin Andresen decided to increase it to 8MB the next year, and then double it every two years. As many bitcoiners disagreed with the idea, the bitcoin project was forked by Andresen’s co-developer Mike Hearn, and a new product was released under the name Bitcoin XT. It would have become implemented if 75% of bitcoin miners adopted the changes.

Despite the endorsement of Bitcoin XT by eight industry leaders including BitPay, Blockchain.info and Circle, it was never accepted by sufficient number of mining pools. By January 2016 the failure of Bitcoin XT became evident, causing Mike Hearn to exit from bitcoin and declare that bitcoin itself was “a failed experiment”.

Alexey Tereshchenko