Hard fork

A hard fork is a significant, irreversible upgrade or change to a blockchain’s protocol that creates a permanent divergence from the previous version. This results in two separate blockchains: one following the old rules and the other adopting the new ones. Hard forks typically occur due to protocol upgrades, security fixes, or disagreements within the community. Notable examples include the Bitcoin and Bitcoin Cash split, as well as Ethereum and Ethereum Classic. Unlike soft forks, which are backward-compatible, hard forks require all participants to upgrade to the new version to continue interacting with the updated network.