On one hand, the core developers want to keep the blocks that make up bitcoin's network limited in their size to protect it from hacks. On the other hand, some miners want to make the blocks bigger to improve the network's speed.
That disagreement means a bitcoin "fork" could occur on Tuesday as the deadline for a decision is set for 8:20 a.m. ET.
According to a blog post from bitcoin exchange Coinbase, a fork is "change to the software of the digital currency that creates two separate versions of the blockchain with a shared history." Coinbase warns that forks can be both temporary or permanent and occur because users may disagree on the best path forward for the cryptocurrency, which could ultimately lead to it splitting in two.
Forks have occurred in cryptocurrencies before. Bitcoin's rival, Ethereum, experienced its own fork in 2016, eventually leading to the creation of the form of the cryptocurrency we know today.
As for how bitcoin will respond to Tuesday's decision, no one knows. But the majority of bets placed on the event are predicting the price will fall from here. Of the 470 people who bet on the event on Bodog, "310 people think the price will dip below $2,000 per coin," according to a company spokesperson.
Bitcoin is up 189% in 2017, trading at $2,808 a coin.
Get the latest Bitcoin price here.