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List of bitcoin forks

Bitcoin forks are defined variantly as changes in the protocol[1] of the bitcoin network or as the situations that occur "when two or more blocks have the same block height".[2] A fork influences the validity of the rules. Forks are typically conducted in order to add new features to a blockchain, to reverse the effects of hacking or catastrophic bugs. Forks require consensus to be resolved or else a permanent split emerges.[3]


Forks of the client software

The following are forks of the software client for the bitcoin network:

All four software clients attempt to increase transaction capacity of the network. The majority hash power did not begin to use these clients. Therefore there was no consensus to change the rules.[4]

Intended hard forks splitting the cryptocurrency

Hard forks splitting bitcoin are created via changes of the blockchain rules, sharing a transaction history with bitcoin up to a certain time and date. The first hard fork splitting bitcoin happened on 1 August 2017, resulting in the creation of Bitcoin Cash.[5][6] A list of hard forks splitting bitcoin by date and/or block follows:

  • Bitcoin Cash: Forked at block 478558,[7] 1 August 2017, for each bitcoin (BTC), an owner got 1 Bitcoin Cash (BCH)
  • Bitcoin Gold: Forked at block 491407,[8] 24 October 2017, for each BTC, an owner got 1 Bitcoin Gold (BTG)
  • Bitcoin Private: Forked at block 511346,[9] 28 February 2018, for each Bitcoin (BTC) or ZClassic (ZCL), an owner got 1 Bitcoin Private (BTCP).

Intended soft forks splitting from not-most-work block

  • The fork fixing the value overflow incident was controversial because it was announced after the exploit was mined.

Unintended hard forks (by 'protocol change' definition)

  • March 2013 Chain Fork (migration from BerkeleyDB to LevelDB caused a chain split)
  • CVE-2018-17144 (Bitcoin 0.15 allowed double spending certain inputs in the same block. Not exploited)

Proposed (but canceled) forks

  • SegWit2x: This was a planned fork which was later canceled before the split could take place.


  1. ^ Tarr, Andrew (July 19, 2017). "UASF vs. UAHF, Explained". CoinTelegraph. Retrieved 22 March 2018.
  2. ^ Antonopoulos, Andreas (2017). Mastering Bitcoin: Programming the Open Blockchain (2 ed.). USA: O' Reilly media, inc. p. Glossary. ISBN 978-1491954386.
  3. ^ Jamie Redman (5 November 2017). "A Simple Guide to What Bitcoin Forks Are and Why They Happen". Retrieved 23 April 2018.
  4. ^ Ammous, Saifedean (2018). The Bitcoin Standard: The Decentralized Alternative to Central Banking. John Wiley & Sons. pp. 227, 228. ISBN 9781119473893. Retrieved 23 April 2018.
  5. ^ "Blockchain Forks Are All the Rage, But Can They Ever Be Safe? - CoinDesk". 19 October 2017. Retrieved 17 January 2018.
  6. ^ "What is Bitcoin Cash? A Basic Beginners Guide - Blockgeeks". Retrieved 17 January 2018.
  7. ^ "Bitcoin Cash - Peer-to-Peer Electronic Cash". Retrieved 2017-12-03.
  8. ^ "FAQ - Bitcoin Gold". Retrieved 2017-12-03.
  9. ^ "FAQ - Bitcoin Private". Retrieved 2018-04-03.