CocoaPods only supports Swift on OS X 10.9 and newer, and iOS 8 and newer.
Here's why:
- Swift is supported on OS X 10.9 / iOS 7 and newer, as stated by Apple numerous times.
- There is no support for building static archives with Swift.
- Dynamic frameworks are supported on all versions of OS X.
- Dynamic frameworks are unsupported on iOS versions prior to 8:
> ld: warning: embedded dylibs/frameworks only run on iOS 8 or later.