No, the purpose of semvar is to be able to distinguish compatible updates from incompatible updates. As a concept it's relevant any time you have a protocol or

No, the purpose of semvar is to be able to distinguish compatible updates from incompatible updates. As a concept it's relevant any time you have a protocol or a communications channel between agents that aren't rigidly kept in sync. Think network protocols, on disk formats... The alternative to semvar in the filesystem world has historically been feature bits, but feature bits suck because there was an order in which you rolled out features and feature bits do not preserve that ordering. Meaning users can (and will, because users do crazy things) end up in a state where they have all the modern feature bits enabled but not the one from 5 years ago and you never tested that configuration. Learn semvar. Use semvar. Semvar good.