Upgrading a Swift 1.1/1.2 project from Xcode 6 to Swift 2 project on Xcode 7

Question

I have a project that I've been working on with my friend on Swift 1.1/1.2. Unfortunately, when I upgraded my Xcode to the latest version, I noticed that the app will no longer compile and there are lots of errors. Is there a way for Xcode 7 to compile for Swift 1.2? If not, how do I get the old version of Xcode which does not use Swift 2?

Is Swift 2 app backward compatible with Swift 1 apps? Can Swift 1.2 app run on iOS 9?

Are most developers using the Swift 2 now or not?

Answer 1

In Xcode start with Edit->Convert->To Latest Swift Syntax...

You may still have errors that you will have to resolve manually. Read the Xcode Release Notes to see what changed in Swift 2.