Fork (Blockchain Fork)

A blockchain fork is a split in the network that results in two diverging paths—either temporary or permanent—each with its own version of the protocol or transaction history. Forks occur due to software upgrades, disagreements within the community, or technical changes in consensus rules. There are two main types of forks. A soft fork is a backward-compatible update where upgraded nodes can still communicate with those running the older version, though old nodes may reject some new blocks. An example is Bitcoin's SegWit. A hard fork, by contrast, is a non-backward-compatible change that creates two separate blockchains unless all participants upgrade. This can be planned—like Ethereum's major upgrades—or contentious, as seen in the creation of Bitcoin Cash from Bitcoin and Ethereum Classic from Ethereum. Forks can also happen temporarily when two miners find valid blocks at the same time. The conflict is resolved when the network accepts the longer chain. Forks are essential tools for blockchain governance and evolution, allowing communities to implement improvements or pursue alternative visions. However, contentious forks may split the user base and dilute network strength, impacting adoption and security.