confusion of how to make osx app backward compatible & how to test them

Question

after reading the apple SDK guide https://developer.apple.com/library/mac/#documentation/developertools/conceptual/cross_development/Overview/overview.html

I\'m still c

Answer 1

Adding to Rob Napier's great in-depth answer:

To use an old SDK, put the SDK (or a symlink) to it here:

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs

With XCode 7.3 or later, you need you to open this file and change "MinimumSDKVersion" (otherwise XCode will refuse to use the old SDK):

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Info.plist