Soft Fork

What Is a Soft Fork?

A soft fork refers to a change in the software protocol of a blockchain that’s backward compatible with older nodes, meaning that older nodes can still recognize new blocks as valid. 

Soft forks can happen at any given time. Miners who don’t upgrade to the latest version of the software can still proceed with their transactions. This is because all blocks in the latest soft fork are based on old rules, thereby allowing previous clients to continue accepting them. 

Some examples of soft forks include Bitcoin’s addition of the P2SH, and the adoption of SegWit. 

It is possible to reverse soft forks. However, the only way to do so is to undertake a hard fork, which is a more drastic and permanent shift in a blockchain’s protocol.

The Difference Between Soft Forks and Hard Forks

Hard and soft forks are largely similar in function in that they’re an essential part of blockchain software development. In essence, a soft fork only requires a majority of miners to upgrade to execute the new rules, resulting in a single viable blockchain. This is very different from a hard fork, which causes a permanent divergence in the blockchain and requires all of the miners to agree and upgrade to the new version in order for it to work. 

Read our in-depth guide on soft forks for more details.