How to Build an Application compatible with older MacOS with Xcode?

Question

I just installed the latest version of Xcode (10.1) on MacOS 10.14 (Mojave). I can build my application and it runs fine on my Mac or similar system.

However, I want to share this application with someone using MacOS 10.11 (El Capitan) and it fails to launch, asking for a minimum requirement of MacOS 10.13 (High Sierra).

My application is only very simple, can't I compile it to be compatible with older MacOS ?

---

After some research, I did download MacOSX10.11.sdk (from https://github.com/phracker/MacOSX-SDKs/releases/). I did decompress it, and drag it into: /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs (This folder originally contains only "MacOSX.sdk" and a link pointing to it, named "MacOSX10.14.sdk")

I also noticed the value of the string "MinimumSDKVersion" from the file /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Info.plist is equal to "10.11", which sounds good in my case.

I read on some forums adding additional SDK versions into Xcode is not supported. And by the way, I cannot see any menu from Xcode to specify my target build (neither in Xcode Preferences, nor in the project settings (see picture below).

Where can I tell Xcode to use, let's say "MacOSX10.11.sdk" over "MacOSX10.14.sdk"?

And, is there a better way?

Or, do I have to install an old version of MacOS on a different partition, with an old version of Xcode (which would be a pain)?

Answer 1

I am not sure if this still works on Mojave, but there is a project called XcodeLegacy which is created specifically with this intention in mind: https://github.com/devernay/xcodelegacy