What is a hard fork？

A hard fork in blockchain occurs when there is a permanent split in the chain, resulting in two separate and incompatible versions of the blockchain network. This happens when there is an update to the protocol or rules governing the blockchain network that is not backward compatible, meaning that nodes using the old version will not be able to communicate with those using the new version.

When a hard fork occurs, the new version of the blockchain typically splits off from the old one and creates a separate chain with its own set of rules, transactions, and blocks. Nodes that decide to switch to the new chain must download and install the updated software to interact with it, while those remaining on the old chain continue to follow the old rules.

Hard forks can occur for various reasons, including differences in the consensus mechanism, fundamental changes to the core protocol, or disagreements among the community over how to address a particular issue. In some cases, hard forks can lead to the creation of a new cryptocurrency, as the new chain may have a different name, ticker symbol, and value, depending on market demand and adoption.

While hard forks can create a new and improved version of a blockchain network, they can also lead to fragmentation and confusion within the community, especially if there is no clear agreement on which chain should be considered the "true" version. Therefore, it's important for blockchain developers and stakeholders to carefully consider the potential impacts of a hard fork before deciding to implement one.