Forks are the splitting of the blockchain into two. This can be intentional or non-intentional. Usually, as a result of major protocol upgrade, a hard fork is created, and unintentional fork can be created due to bugs in the software.
With the release of Homestead, due to major protocol upgrades, it resulted in a hard fork. The protocol was upgraded at block number 1,150,000, resulting in the migration from the first version of Ethereum known as Frontier to the second version of Ethereum called Homestead. The latest version is called Byzantium which is the first part of the Metropolis release. This was released as a hard fork at block number 4,370,000.
An unintentional fork, which occurred on November 24, 2016, at ...
