Michael HuletTreehouse Moderator 47,037 Points
Since Swift 4 was only just released, the current Swift courses are all in Swift 3. However, Swift 3 is still perfectly valid syntax in most cases, but it'll be 100% valid all the time if you set the compiler for your project to run in Swift 3.2 mode. That being said, there's currently a What's New in Swift 4 workshop where you can get a feel for the differences and start to use them in practice
Zachary BrowneiOS Development with Swift Techdegree Student 195 Points
Have the videos in IOS Development Techdegree been updated to Swift 4? It has been out for a while now.