Summary A subsection of the Bitcoin economy including prominent businesses such as Coinbase, Xapo, and BitPay have signed an agreement to adopt and implement a contentious hard fork of Bitcoin sometime in November. A hard fork is a backwards incompatible change to the Bitcoin network. This hard fork is not supported by the majority of the Bitcoin users and developers and is therefore a contentious hard fork. By adopting this hard fork, we believe the supporters of this agreement are shifting their users to an alternative currency (an altcoin) which is incompatible with Bitcoin. The signatories of this agreement wrongly believe that the currency created by adopting this contentious hard fork will eventually become Bitcoin. Therefore storing any BTC on services such as Coinbase, Bitpay and Xapo is strongly not recommended. By storing BTC on these services, you could find that after the hard fork, your BTC has been renamed to something else or replaced entirely with the new altcoin. The best way to ensure that your BTC is protected is to download the latest version of Bitcoin Core and transfer out any BTC stored on services that are a signatory to this agreement. We have listed the businesses supporting this contentious hard fork at the bottom of this document. For users who aren’t prepared to install Bitcoin Core and go through the lengthy set up process, we recommend a wallet such as GreenAddress, Electrum or TREZOR. Avoid using web wallets like blockchain.info. However users should only use these wallets to store their coins and never perform transactions until well after the hard fork. Any transactions you make on the Bitcoin blockchain can also be replicated and “replayed” on the altcoin chain. If the coins on the contentious hard fork have any value, there will be methods you can use to “split” your coins and have access to them. Pay extra attention to major Bitcoin communication channels and media shortly after the fork so you stay informed.

Mobile wallets Miners in Bitcoin are responsible for transaction ordering through putting transactions into blocks, and collectively creating a chain of these blocks. Most mobile wallets depend on blindly trusting the longest chain produced by the miners in order to safely send and receive transactions. There is considerable mining power supporting the contentious hard fork. A majority of miners have pledged to support the contentious hard fork, therefore the longest chain as seen by most mobile wallets may not be the true block chain. As a result of this, spending money from a mobile wallet during a hard fork is dangerous. You will be vulnerable to many attacks as your wallet is not aware that the miners are breaking the consensus rules on the longest chain. If the contentious hard fork has failed and the majority of miners have broken their pledge to support the hard fork, it is safe to continue using mobile wallets, however you should check multiple sources of Bitcoin news such as this website, /r/bitcoin, and the Bitcoin Forum to make sure that it’s safe to continue using your particular wallet. As a general rule, you should not perform any transactions during and shortly after the hard fork.

After the fork Blocks may be slower shortly after the hard fork and your transactions will take longer to confirm. You will have to pay a higher transaction fee if your transaction is high priority and you want it confirmed in the next block. You should try to get any important transactions done a few days before the hard fork date. A lot of websites and programs will likely pop up around the time of the hard fork offering to split your Bitcoin so you can have access to both your BTC and to the new altcoin created by this contentious hard fork, you should exercise caution as many of these services are likely to be scams trying to steal your bitcoin. As the hard fork has very little replay protection, most transactions you perform on the Bitcoin network will also be valid on the hard fork network. You should keep this in mind when transacting. Some services may continue to present and name the altcoin created by this contentious hard fork as Bitcoin. Users should be aware that this new currency is not Bitcoin. Bitcoin can only be changed with the overwhelming consensus of the entire Bitcoin community of individuals, miners, developers and economy. Even when there is overwhelming consensus, unless in an emergency, a hard fork should have at least a year notice period to give enough time for users to upgrade. This hard fork being adopted by the signatories of this agreement achieves none of these things. It is a rushed and hasty upgrade which only has minority community support and has been thoroughly rejected by users and the technical community. As this new altcoin is not Bitcoin, Bitcoin.org will not list wallets and services that present this altcoin as “Bitcoin” or “BTC” to their users after the hard fork. These services have exited the Bitcoin system in a contentious manner and therefore are no longer useful to our visitors. The following companies and services have pledged to adopt the contentious hard fork:

Wallets Abra (United States)

Bitcoin.com (St. Kitts & Nevis)

BitPay (United States)

BitPesa (Kenya)

Blockchain.info (UK)

BTC.com (China)

Circle (United States)

Coinbase (United States)

Coins.ph (Phillipines)

GoCoin (Isle of Man)

Jaxx (Canada)

Luno (Singapore)

Ripio (Argentina)

Unocoin (India)

Xapo (United States)

Exchanges ANX (Hong Kong)

Bitex (Argentina)

bitFlyer (Japan)

Bitso (Mexico)

BTCC (China)

BTER.com (China)

Coinbase (United States)

Coins.ph (Phillipines)

CryptoFacilities (UK)

Korbit (South Korea)

Safello (Sweden)

SFOX (United States)

ShapeShift (Switzerland)

Miners 1Hash (China)

Bitcoin.com (St. Kitts & Nevis)

Bitfury (United States)

Bitmain (China)

Bixin.com (China)

Genesis Mining (Hong Kong)

ViaBTC (China)