UPDATE, 11/10/17: Several companies including Bitmain (a large miner) have suspended Segwit2x efforts. We are still monitoring the situation, but we now believe that bitcoin miners will not activate the protocol change as expected.
Some background on Segwit2x
A majority of Bitcoin miners have signaled their intent to deploy Segwit2x, a Bitcoin protocol change which increases the base size of Bitcoin transaction "blocks" (groups of bitcoin transactions). The final part of this change is scheduled to occur when Bitcoin block #494,784 is mined. Right now, this protocol change will likely activate in mid-November.
In some cases, in-progress protocol changes can temporarily increase the risk of using the Bitcoin network for payments. These risks include the increased risk of sending or receiving double-spend transactions.
How to stay secure during the protocol change
Absent any further developments, we strongly recommend that you stop sending or receiving Bitcoin payments prior to [Bitcoin block 494,784](https://insight.bitpay.com/blocks" target="_blank) (allowing time for your transactions to get into a prior block) and until the protocol change is complete. Before the protocol changes are complete, there may be significant risk of double spends and unintended loss of funds due to a possible network split.
We will send our wallet users another notification when we determine that payment risks have passed.
FREQUENTLY ASKED QUESTIONS
Could the bitcoin network split over Segwit2x?
While most miners signaled their support of the Segwit2x protocol change, not all support it. If miners are divided over this change, there is a significant risk of a chain split.
If there is a network split, which block chain will BitPay's services use?
If a chain split occurs, BitPay’s services will follow the chain with the most accumulated difficulty. We will refer to the minority chain as BC1 (if Segwit2x is the majority) or BC2 (if Segwit2x is the minority).
Learn more about how BitPay will respond to a network split.
Will I be able to access BC1 or BC2 from the minority chain?
In the event of a prolonged or permanent chain split, if the minority chain has significant market value, we will provide you instructions on how to safely access those coins.
Will I be able to send payments on the minority chain?
We have no plans for our wallet to host or send payments on the minority chain. Learn more about why BitPay processes payments on the block chain with the most accumulated difficulty.