Installing an Older Version of Xcode Alongside Xcode 9

Today I started working on updating Apport code from Swift 2 to Swift 4. So I got everything ready, made a fresh cup of coffee and opened the project workspace in Xcode 9. And then I got this message:

I have to convert the project to Swift 3 first in Xcode 8 and then convert once again to Swift 4 in Xcode 9.

So I need both Xcode 8 and Xcode 9 installed, and here is how that can be done:

Install

1. Download Xcode 8.3.3 from Apple Developer Downloads. You will receive a file named Xcode8.3.3.xip which is a digitally signed zip file.

2. Expand the xip file. It will be expanded to Xcode.app

3. Rename Xcode.app to Xcode8.app

4. Drag Xcode8.app to your Applications folder

Selecting Xcode version

Switch to Xcode 8

sudo xcode-select --switch /Applications/Xcode8.app

Switch to Xcode 9

sudo xcode-select --switch /Applications/Xcode.app

Print version that is selected

xcode-select --print-path