Swift 3.1
Swift 3.1 is a minor release that contains improvements and refinements to the Standard Library. Thanks to efforts by IBM and other members of the community, it also includes many updates to the Linux implementation of Swift. There are also a number of updates to Swift Package Manager. In addition, the Swift 3.1 compiler now automatically precompiles Objective-C bridging headers, which can speed up debug configuration builds of mixed-source projects.
This was a smooth update for me.
Update (2017-03-28): Károly Lőrentey:
Favorite Swift 3.1 feature not mentioned in the release notes: you can now define extensions for specific generic arguments 🌱
