How to write apps in xcode 6.1 to run in iPhone 4s or earlier

Question

I am working on Xcode 6.1 and built an application that runs perfectly on iPhone 5s and later simulators. More information on the application:

• The app uses a static library(with 64 bit architecture).
• Base SDK: iOS 8.1
• Deployment target: 8.1

Now, when I try to run the app on iPhone 5 or iPhone 4s (or earlier) simulators, it fails to build with Apple Mach-O Linker errors and warning. I guess it might be compiled in 32 bit architecture to solve this. But should I even change the architecture of the library (which is in my scope)? If so, how can that be done? I tried many times by changing the architectures of both the app and library to 32 bit but failed.

Any help on this is appreciated.

Answer 1

Your static library needs to be built for both 32 and 64 bit just as your app is. 64 bit only existed in the 2013 released devices.