Fork

A fork is a divergence in a blockchain’s rules or history. It happens when participants adopt different versions of the protocol, splitting the single agreed path into two.

How it works

A soft fork tightens the rules in a backward-compatible way, so nodes that do not upgrade still accept the new blocks. A hard fork changes the rules in a way that is not backward-compatible; if part of the community keeps running the old rules, the chain permanently splits into two networks, each with its own coin and history from the split point onward.

Why it matters

Forks are how decentralized networks upgrade and how disagreements get resolved when consensus breaks down. A contentious hard fork can create an entirely new cryptocurrency and divide a community, while routine soft forks let a network improve smoothly.

Example

Bitcoin Cash split from Bitcoin through a hard fork over how to scale the network.