Maybe someone will explain this to me. Does Swift use this confusing "rapid release" versioning? Does Swift 4 break backwards compatibility with Swift 3? In my company people are looking for a language to rewrite some legacy Objective-C to. Swift is often discarded as "unstable" because of these major version bumps. Compare this to Go, which, seven or so years after the initial release is still 1.x and still doesn't…
However, this was only in the early releases. The plan is to stop breaking changes soon and freeze the ABI. They're a little behind schedule for this, but it should happen soon.