You can query the NSFoundationVersionNumber like so:

    if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1) {
        // you're running iOS 6.1 or earlier
        
    } else {
        // you're running iOS 7 or later
        
    }

Note that if you’re compiling with an older SDK, the value you’re querying may not be defined – in which case, you must define it manually at the beginning of your class:

#ifndef NSFoundationVersionNumber_iOS_6_1
#define NSFoundationVersionNumber_iOS_6_1 993.00
#endif

You can find other NSFoundationVersionNumbers here:

• https://developer.apple.com/library/ios/documentation/Cocoa/Reference/Foundation/Miscellaneous/Foundation_Constants/Reference/reference.html