Do I need to build my project with the latest available version of Xcode available on the Mac App Store for submission or can I use the older version

Question

I was going through app review guidelines and one thing which I am unable to find the answers is

"Do I need to build my project with the latest available version of Xcode available on the Mac App Store or can I use the older version "

For example the current version of Xcode available on Mac App Store as of writing of these lines is Xcode 9.0, so do I need to build my project using Swift 4 and Xcode 9.0 or can I use older versions (say Swift 3.x and Xcode 8 or Xcode 7).

A similar question was asked in Feb 2012 Do I need the latest version of Xcode to submit apps to the app store? .

But it doesn't provide clear cut answer and the answer is more than 5 years old. And during that time the language for choice was objective -C whose versions were and are more stable than current lingua franca, Swift.

Answer 1

You can use older version of Xcodes (Xcode 8.x) to develop and upload your project build on app store. There is no any such kind of restriction by Apple, that you must use latest Xcode Tool to upload a build on the store

I recommend and a as good advise,

You should use latest version of Xcode Tool to make your app, compatible with latest version of technology. You should see and implement, changes in technology. And one most important and major update in Xcode 9 is - support for iPhone-X device. To see your app interface is compatible with iPhone-X or not, you must use Xcode 9. There are so many other considerable updates in Xcode 9 (with iOS 11)

Here is list of updates with Xcode 9: Highlights of Xcode 9

It's not required to convert/change version of Swift programming language to provide a support of latest Tool.

Xcode 8.3 & Xcode 9, both supports Swift 3.2 version. So, if your current project is supporting, Swift 3.2 version, then you can easily work with Xcode 9.0

How to see current Swift version of your Xcode Project

Also, review this answer to see, how you can make your project compatible to Xcode 9 - Xcode 9 Swift Language Version (SWIFT_VERSION)

Here is nice answer from Apple:

Why You Should Use the Latest SDK
Building with the latest SDK gives your app all possible bug fixes and new behavior. For compatibility reasons, frameworks can't always expose improved behavior, unless apps are built with the latest SDK.

For example, when Retina enabled iPads were first introduced, only iPad apps built with the very latest iOS SDK could create Retina images by simply loading an image with an @2x suffix.

By building with the latest SDK, apps signal that they are ready for all API improvements and bug fixes.