In a post on the bitcoin developer mailing list, Hearn said that he felt a fork was the only option for solving the deadlock within the community: “I feel sad that it’s come to this, but there is no other way. The Bitcoin Core project has drifted so far from the principles myself and many others feel are important, that a fork is the only way to fix things.”

The key difference between Bitcoin XT and the other version of bitcoin, known as Bitcoin Core, is size of the blocks into which transactions get grouped every 10 minutes. Core supports a maximum block size of 1mb, which XT increases to 8mb. Hearn, and the other supporters of XT, argue that that increase is necessary if the currency is to continue growing.

“As Bitcoin spreads via word of mouth, we will reach the limit of the current system some time next year, or by 2017 at the absolute latest,”Hearn writes . “So it is now time to raise the limit, or remove it entirely.”

Those who oppose the change do so for a variety of reasons. Some argue that it’s a simple sticking-plaster solution, and that the actual fix should be far more wide-ranging.

Others simply oppose changing anything from the initial bitcoin proposal presented by Satoshi Nakamoto in 2009, and argue that any major change should come in the form of a whole new currency, or “alt coin”, rather than an update to bitcoin itself.

One opponent, posting to the bitcoin-dev mailing list, even claimed to be Nakamoto himself .

“The developers of this pretender-Bitcoin claim to be following my original vision, but nothing could be further from the truth,” they wrote. “When I designed Bitcoin, I designed it in such a way as to make future modifications to the consensus rules difficult without near unanimous agreement. Bitcoin was designed to be protected from the influence of charismatic leaders, even if their name is Gavin Andresen, Barack Obama, or Satoshi Nakamoto. Nearly everyone has to agree on a change, and they have to do it without being forced or pressured into it. By doing a fork in this way, these developers are violating the ‘original vision’ they claim to honour.”

The poster’s claim to be Nakamoto was widely derided, since the message wasn’t cryptographically signed, something the real Nakamoto frequently did to prove his identity. Nonetheless, Hearn - who says that the message “could be from anyone” - argues the fake Nakamoto’s input proves a point.

“There’s an interesting thing here - what if Satoshi did come back and weigh in? Let’s imagine he turned up and said he’d rethought, and Bitcoin was a bad idea. Should everyone just give up and walk away? Or accept that people’s ideas do change. My article quotes Satoshi a lot, but that’s not to imply he’s some sort of god or absent dictator.”

In the short term, Hearn argues that most bitcoin users can safely ignore the debate. Unless they are “mining”- running the software that verifies bitcoin transactions - bitcoin users effectively have no vote in which one of the competing proposals becomes the future of bitcoin, while the software they use to make payments in the currency will likely support the biggest of the two networks.

The worst-case scenario for the currency is that both Bitcoin XT and Bitcoin core continue to exist alongside each other for a long period of time, with neither fully seizing the mantle of the true heir to Nakamoto’s vision. In such a situation, the currency’s uncertain future could prove permanently damaging to its prospects.

But even if the change goes through relatively quickly, some inattentive users could find themselves out of pocket. Once the block sizes increase (which won’t happen until January 2016, and then only if 75% of the miners have switched to Bitcoin XT), the two versions of bitcoin will be incompatible. Transactions made on one version of bitcoin would not be reflected on the other, essentially rendering null any attempts to spend bitcoin on the “losing”fork after that date.