What is a fork?
Sometimes consensus rules can be modified to add updates or protect the network from attacks, or changed for specific purposes, such as giving birth to a new cryptocurrency. Regardless of the reason for the change, there are two ways to change the rules: via a soft fork or hard fork.
In both soft forks and hard forks, users must participate in upgrading the network either by downloading new software and running upgraded nodes or by refraining from doing so, if they choose to do so. Regardless of the way in which the change is carried out, it is necessary to develop applications that take advantage of the update made.
When forks are used to upgrade the network in question, it is necessary to reach the adoption threshold by the network nodes, previously agreed upon and implemented in code by the protocol developers. If, on the other hand, you want to create a new cryptocurrency, consensus is not a problem. The developers of the new blockchain specify the new parameters and a starting point regarding the forked chain.
A fork occurs when a community changes protocols, forks do not occur only in blockchains, but many software forks also occur, especially in source code.
Within the forks, we can distinguish between two main types, soft forks and hard forks:
1) Soft Forks: A soft fork is an update that tries to improve the functionality of the network. As the changes are compatible with the previous protocol, all nodes can continue to process the same blockchain. A soft fork is like upgrading Windows computer software, migrating previous settings to the new version. In this case, the changes are light, and allow a small part of the original protocol to be improved, maintaining the same structure and solidity in the network. However, sometimes there are deeper issues that divide the community based on various discrepancies, whether philosophical, purpose or feasibility, this is what usually leads to hard forks.
2) Hard Forks: A hard fork is an upgrade that is not compatible with previous blocks. The miners processing the original blocks are separated from those processing the updated transactions, creating a completely new program. All miners will share the same ledger until the hard fork, at which point they will work completely independently. To give us an idea of how popular cryptocurrency forks are, there are currently over 70 Bitcoin and 5 Ethereum forks.