An ongoing debate is threatening to tear bitcoin in two

An ongoing debate wracking the bitcoin community became significantly more heated this weekend after two high-profile developers released a competing version of the codebase - risking splitting the digital currency in two.

For the past several months, developers and bitcoin users have debated the merits of increasing the "block size."

A block is a record of recent transactions, and currently has a 1MB limit; increasing it would allow more transactions on the network at once, helping it to scale up to meet growing demand. But it would also make it more difficult for ordinary users to host full network "nodes" that validate new transactions on the network, potentially making the digital currency more centralised as a result.

Because bitcoin is open source (meaning the full code is available for anyone to alter) and decentralised, no one can unilaterally push an update on other users without widespread consensus - consensus that has so far been lacking. Gavin Andresen and Mike Hearn, two high-profile developers, have now released Bitcoin XT, an alternative version of the core software that supports increasing the block size when required. Bitcoin users will now be forced to decide between "Bitcoin Core" and Bitcoin XT, raising the prospect of a "fork," where the digital currency divides into two competing versions.

Right now, Core and XT are compatible, and both exist on the same blockchain, the public ledger of all bitcoin transactions shared across the network. Bitcoin is still running as one digital currency. However, if XT is adopted by 75% of users by January 2016, it will upgrade to a larger block size. This will be incompatible with Core - meaning that if the other 25% don't then choose to convert, it will effectively split the currency into two.

But will it work?

The choice between XT and Core can be thought of as a kind of referendum on the block size debate, brought about after months of heated discussion failed to come to a consensus decision. So far, 7.7% of the network has adopted XT, according to website XTnodes.com. It's a relatively quick uptake, but it remains to be seen whether it can reach 75% by next year.

Samson Mow is the COO of BTCChina, one of the largest mining pools. A mining pool is a group of users who pool their resources to improve their chances of successfully "mining" bitcoin - authenticating transactions on the network in return for a bitcoin reward. He told Business Insider that BTCChina and the broader Chinese mining community "has decided not to adopt Bitcoin XT. The foundation of bitcoin is consensus and what we need is for core devs to reach consensus on changes to bitcoin core. Without that consensus from the core devs, it falls upon the mining community to maintain the stability of bitcoin, and that is what we will continue to do."

Collectively, the biggest Chinese pools make up more than half the network. If they refuse to adopt XT, it's difficult to see how it can reach the 75% majority it requires to increase the block size.

That said, Hearn remains confident. "At the moment, we think it's plausible we can get majority," he told CoinDesk. "But it will likely be a lot of work."

The return of Satoshi Nakamoto (or not)

During this weekend's discussion on the bitcoin developer mailing list, a user purporting to be Satoshi Nakamoto - the mysterious creator of bitcoin - chimed in on the subject, condemning the XT project. However, the email was not cryptographically signed, and is probably a fake - Satoshi's email accounts have been hacked before, after all.

Even if XT isn't adopted, it's possible that its creation will create new urgency and help encourage a clear decision on the block size debate sooner than would otherwise be the case. The Chinese mining community, while not supporting XT, does in principle support an increase in size.

But the ongoing debate and failure to risk consensus about this important issue also risks spooking the general public, damaging the digital currency's image and risking its chances of more mainstream adoption.