According to the Coinbase’s FAQ page, Bitcoin Segwit2x is a proposed change which is intended to improve the speed and cost of Bitcoin transactions. If the upgrade is not universally accepted, it may temporarily create two Bitcoin blockchains via a fork of the Bitcoin network. The Bitcoin Segwit2x fork will take place when block #494,784 is mined. This is projected to happen on November 16.
Coinbase explained there will be no needed action by their clients, and all users with a balance of BTC will receive an equal amount of the B2X asset on the Bitcoin2x blockchain. If a customer has 5 BTC stored on Coinbase before the fork, he will have 5 BTC and 5 B2X after the event. It is necessary to emphasize that pending BTC purchases at the time of the fork will not be granted any B2X.
During the 24 hours pre-fork, Coinbase will temporarily disable all bitcoin buy, sells, sends and receives. ETH and LTC will not be impacted. Clients will still be able to see Bitcoin balances and monitor the price. If user plans on moving BTC into his account, Coinbase highly recommend to do that at least 24 hours before the fork to ensure transfers are confirmed. After 24–48 hours post fork, if Coinbase ensure that the blockchains are stable, it will re-enable Bitcoin and Bitcoin2x sends and receives.
“Following the fork, we will continue referring to the current bitcoin blockchain as Bitcoin with the symbol ‘BTC’. We will refer to the new blockchain resulting from the fork as Bitcoin2x with the symbol ‘B2X’. If the Segwit2x change is accepted by most users, we may choose to rename these blockchains at a later date.”
Also, it is necessary to note that one more update on Bitcoin Gold is provided by Coinbase. Bitcoin Gold is already active. The process for this hard fork started early July this year and the technical team behind the Bitcoin Gold has recently released a “snapshot” of the Bitcoin blockchain giving a birth to a new cryptocurrency at block 491,407 on the original blockchain. This means that Bitcoin blockchain can now be tweaked, reconfigured and recreated with new set of rules. With regard to Coinbase’s position on Bitcoin Gold, on October 23, 2017 it stated the Bitcoin Gold hard fork already happened, two days before planned.
The wallet provider BTC.com revealed this decision to support both sides of the chain after the fork, as did with the Bitcoin Cash fork this past August. The reason for this is that the wallet provider said that it has designed its own form of replay protection. On the contrary, the Hong Kong-based exchange Gatecoin refused to support the Segwit2x hard fork and motivated it with the fact that there is a lack of two-way replay protection for this hard fork is the main reason they dislike.
In this way, Coinbase, BTC.com, and Gatecoin join the growing list of bitcoin-based companies revealing their plans for the Segwit2x fork.