Swift 4 Release Process

Swift 4 is a major release that is intended to be completed in the fall of 2017. It pivots around providing source stability for Swift 3 code while implementing essential feature work needed to achieve binary stability in the language. It will contain significant enhancements to the core language and Standard Library, especially in the generics system and a revamp of the String type.

→ swift.org/blog/swift-4.0-release-process/

Swift 4 is a major release set for fall 2017. It focuses on source stability for Swift 3 code and essential features for binary stability, with big updates to generics and the String type.

The compiler offers two modes: one keeps compatibility with Swift 3.1, and the other adds new changes like String API overhauls that break sources but allow gradual migration across modules. Daily snapshots come from the swift-4.0-branch, with development on master until early summer 2017, after which only key fixes enter via pull requests under strict rules. Release managers oversee the process for various repositories, and all language changes go through Swift Evolution.