Updates & Forks

While Bitcoin is generally resistant to change and doesn't change as often as other chains might, that doesn't mean it is completely stagnant. There have been several changes and upgrades over the years.

In general, these changes can be divided into two categories: hard forks and soft forks.

Hard Forks

A hard fork is where the chain splits and creates an entirely new version. The new chain is not backward compatible and nodes need to choose between the two.

There have only been a few long-lasting hard forks in Bitcoin's history, Bitcoin Cash is one of them after the heated blocksize war, which is a fascinating read.

Bitcoin also accidentally hard forks relatively frequently for a short amount of time, we discussed this when we talked about chain reorganization above.

Hard forks are a radical change that should only be carried out when absolutely necessary, as it is necessary to get the entire network to agree in order to have them switch to the new chain and not create two versions, as with Bitcoin Cash.

Soft Forks

In contrast, soft forks are backward compatible changes where nodes see both versions of that chain as valid. SegWit was a major upgrade to the Bitcoin network that we'll talk a bit more about below and was a soft fork.

Bitcoin also has a very cool ability called user-activated soft forks. UASFs allow users of Bitcoin like wallet operators, exchanges, businesses, and other users running full nodes to move to a new version of a chain that will have some activation point in the future.

This forces miners to utilize this new forked version or else end up mining a separate chain, killing their profits. This is primarily to prevent control of the network from being in the hands of the miners, which was a major concern during the blocksize war.

We recommend anybody interested in the surprisingly dramatic history of Bitcoin forks read the book linked above, The Blocksize War.

Two major upgrades to Bitcoin that we recommend you read more about are SegWit and Taproot, as they both have impacted how Bitcoin works in relatively major ways.