Hard Fork

A hard fork in blockchain is a type of protocol change that validates all of the previously invalid transactions and invalidates all the previously valid transactions. These are the major events and are preliminarily broadcasted to the community of a cryptocurrency in advance. Example: The proposal to hard fork Bitcoin (BTC) in 2017 in the bid to increase its block size from 1 MB to 8 MB for the faster and more transactions had been met by the strict opposition from the majority of the community.