You would have a painful time if large but innocuous architectural changes introduced major version bumps. Semantic versioning is how many packaging ecosystems nowadays work and decide compatibility. There is only one question to answer: Did the architecture change change the public API? No: even if this was an entire application rewrite, users don’t care. This is not a new major. Perhaps not even a minor (this is subjective I guess). Yes: it’s a breaking change and warrants a major version bump. So the scale of changes is sometimes at odds with the scale of the resulting version bump. Huge changes might not even be fixes, single-line changes might result in major version bumps. All this is highly important for libraries to adhere to. Binaries/programs possibly less so.