dyld`dyld_fatal_error: Apparently app crashes on launch because of bad linking

I have Xcode 6.1.1 and set my deployment target to 7.1. Base SDK is the latest 8.1 as advised here in the forum and Apple.

However, when I run the app in the simulator with iPhone 7.1, it crashes on launch:

dyld: Symbol not found: _objc_isAuto
Referenced from:/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation
Expected in: /Applications/http://ift.tt/1i7W72Q
in /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation

Users with iOS 7.1 also report that the App is crashing. From what I read here in the forum, is that it is not related to code, but to a bad linking on simulator and iOS 7.1 devices. The App was reviewed by Apple and passed, so I assume that at least on Apple's iOS 7.1 devices, this doesn't happen.

Is there a fix to this? Wrong build configuration. I would like to select 7.1 as the base SDK, but this is not possible, I can only choose the latest 8.1 in Xcode.

Any ideas?