A hard fork in blockchain technology is a permanent divergence from the previous version of a blockchain, resulting in two separate chains. This change is not backward compatible, meaning nodes running the previous version will not be able to validate blocks on the new chain. Hard forks typically occur when there is a fundamental change in the protocol or rules of the blockchain, leading to a split in the network. This can result in the creation of a new cryptocurrency if the community decides to support the new chain.
