San Francisco font in iOS 8

Question

I'm designing an app with the new SF fonts by Apple. To get the new SF fonts in the app, when building for iOS 9 you can just select "System font" in interface builder and it works. But the problem is that for earlier versions of iOS, the "System font" is actually Helvetica Neue, so that replaces San Francisco. How do I force San Francisco to show up on all devices?

Answer 1

This is stated in the license agreement of the San Francisco font:

3. No Transfer. Except as otherwise set forth herein, you may not transfer this Apple Font without Apple’s express prior written approval. All components of the Apple Font are provided as part of a bundle and may not be separated from the bundle and distributed as standalone applications.