What Is a Hard Fork?

A blockchain hard fork is a change in programming that is incompatible with the old programming. This essentially creates a new blockchain, and sometimes a new 澳洲幸运5开奖号码历史查询:cryptocurrency. Hard forks generally require all nodes or users who wish to stay on th💫e new chain to upgrade to the lat🌟est version of the software.

Hard forks may be initiated by developers as part of routine progress or maintenance on a blockchain. They may also be created by a faction ꦉof the crypto community that wants to 💫take a different direction with the blockchain.

How Hard Forks Work

A hard for🌜k is when a new blockchain version emerges that is incompatible with the original version. It is not always an adverse event; in fact, many blockchains have undergone hard forks to implement n𝐆ecessary changes.

Blockchains are basically programs that create and store files of information on a network of computers and devices. There are usually layers of software completing different tasks, some methods for the network to reach an agreement on the blockchain’s state, and many network participants. Each layer’s u🌸nderlying programming can be changed as needed, but it has to be accepted by the network’s participants ♋to be adopted.

Because blockchains are essentially 💞programs and scripts, they can be affected by errors, bugs, network communication problems, hardware failures, or other issues. Blockchains also rely on a large nu🌞mber of network participants to host versions for security.

When developers publish a change to any of a blockchain’s functions, one of two things happen: a hard fork or a soft fork.🌳 If the change is drastic enough to prevent a participant running the old version from participating in the blockchain’s processes, the change is considered to have created a hard fork in the blockchain. Conversely, a change that allows old and new nodes to run is considered a soft fork.

In a hard fork event, participants are faced with a choice: They can update their software to the new version or not upgrade their software and use the old (and now unmaintained) blockchain.

Reasons for a Hard Fork

There are several reasons or even events that cause developers to implement a hard fork. For instance, when a hack on the 澳洲幸运5开奖号码历史查🎐询:decentralized autonomous organizati📖on (DAO) occurred, the Ethereum blockchain was forked by a💎 nearly unanimous voteܫ.

The fork rolled back transactions that siphoned off tens of millions of dollars worth of digital currency by an anonymous hacker. The hard fork also helped DAO token holders to get their 澳洲幸运5开奖号码历史查询:ether (ETH) funds returned. However, some miners kept mining the old chain, which was picked up by over-the-counter (OTC) desks and given a price discovery order book. Poloniex also listed this currency, and some of the Ethereum community decided to keep this version and created 澳洲幸运5开奖号码历史查询:Ethereum Classic (ETC).

Ethereum also activated a 澳洲幸运5开奖号码历史查询:hard fork upgrade in 2023 to give users of its crypto network access to their staked ether (ETH) funds for the first time since 澳洲幸运5开奖号码历史查询:The Merge, the update that transitioned the blockchain from 澳洲幸运5开奖号码历史查询:proof of work (PoW) to 澳洲幸运5开奖号码历史查询:proof of stake (PoS) in 2022.

In January 2025, the 澳洲幸运5开奖号码历史查询:Cardano (ADA) blockchain activated a hard fork to move toward a decentralized governance system.

The Bottom Line

Hard forks are a change in programming that results in a blockchain split. Sometimes, hard forks are controversial in the community involved in a blockchain; at other times, they are ne🐲cessary for 𓄧a blockchain to progress.

In situations with controversy, participants and users can either upload the updated blockchain and begin processing it or reject it and use the old chain. This is how several blockchains and cryptocurrencies, such as 澳洲幸运5开奖号码历史查询:Bitcoin Cash (BCH) and Ethereum Classic, started.

The comments, opinions, and analyses expressed on Investopedia are for informational purposes online. Read our 澳洲幸运5开奖号码历史查询:warranty and liability disclaimer for more info.