I have noticed a lot of people on the Vapor slack asking about how to migrate to Swift 4 so I thought I would write a short post about it. Whilst some of this may be relevant to iOS, for the most part it is concentrating on Swift Package Manager so mainly applies to Server-Side Swift. I also won't talk much about the language changes - there are far better posts that already do!
Swift 4 is out! With the release of Xcode 9 this week, most people are now probably running Swift 4. The highlight is that the list of things you need to do for the most part to get your app working in Swift 4 is....NOTHING!
Remember the major upheaval when Swift 3 came out? There were breaking changes galore and you had to do two or three runs of the migrator in Xcode and even then you were still left with hundreds of errors. Now that Swift is another year older and another year maturer, the migration is a lot smoother.