How do I install Xcode 9 without updating macOS?

Question

Does anyone have any idea to install Xcode 8 OR Xcode 9 without updating macOS?

I want to update my Xcode 7.1 to Xcode 8 or Xcode 9 (or 9.1) Beta.

But it is not allowing me to update directly on OS X Yosemite 10.10.

And I don't want to update my OS to El Capitan now, so how can I install Xcode 8 on OS X Yosemite 10.10.

Answer 1

Xcode 8 will work on OS X 10.11 (El Capitan) but the apps you build with won't, because the only SDK available is macOS 10.12 SDK, i.e. macOS Sierra's.

From release notes:

Compatibility

Xcode 8 requires a Mac running macOS Sierra 10.12 or OS X El Capitan 10.11.5 or later.

Xcode 8 includes SDKs for iOS 10.0, watchOS 3.0, macOS Sierra 10.12, and tvOS 10.0.

Answer 2

To install Xcode 9 without updating macOS you can change the minimum required version in the Xcode bundle's plist. To do that simply control-click Xcode app, click Open Package Contents, then go inside Contents folder, there you'll see info.plist. Open it with Xcode you have already installed, and there you can edit value of Minimum system version field to whatever version you have currently installed.

Also there would be some other "*.app" like "Instruments.app" and etc. They also requires the same operations.

If after all you get the same error, try to Restart your macOS.

I have used that way to install Xcode 9.2 on macOS 10.12.5 and it works.