Bitcoin erased the initial gains it saw after developers last week appeared to avoid a currency split.
Disagreement over other upgrade proposals could still cause bitcoin to split.
The digital currency briefly fell below $2,500, little changed for July.
Bitcoin slammed by more than 10% to below $2,500; Ethereum down big too Bitcoin slammed by more than 10% to below $2,500; Ethereum down big too
Wednesday, 26 Jul 2017 | 8:26 AM ET | 00:46
Bitcoin fell to its lowest in five days Tuesday amid uncertainty over whether the digital currency will still avoid a split.
Bitcoin dropped more than 10 percent to $2,487.13, its lowest since last Thursday when it hit a low of $2,276.16, according to CoinDesk.
The digital currency last traded just below $2,500, unchanged for the month but still more than double in value for the year.
Bitcoin one-week performance
Last Thursday, more than 80 percent of developers signaled support for BIP91, a bitcoin improvement proposal intended to resolve differences between the Aug. 1 User Activated Soft Fork and SegWit2x.
Now, there's worry that activation of SegWit2x might not go smoothly.
"I believe the market is currently somewhat torn between the optimism around BIP 91 locking in, which could lead to SegWit activating if all goes smoothly, and the fear of the second half of SegWit2x proposal, the 2MB block size hard fork, still being contested," Alex Sunnarborg, research analyst at CoinDesk, told CNBC in an email.
Developers must unanimously agree on the 2MB block size by its scheduled November implementation, otherwise bitcoin will split.
