This is not a Qt Question, even thou it can be related to Qt and other applications. Qt has been wisely choosen because it runs on Windows, Linux and MacOS for professional applications. The question again: How to set up a separate sdk version for different apps? Further background: I need to setup SDK 10.15 but it is not listed here: https://developer.apple.com/download/all/ Help regarding the initial question is appreciated. A step by step proceedure would be perfect. Thank you.