Application working fine in iOS 8 device but crashing in iOS 7 devices

Question

I have developed application using Xcode 6 which is using auto layout and size classes . It is working fine in iOS 8 devices but there is problem while running application on iOS 7 devices. In one view controller the application is crashing with the following exception :

*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UIView 0x7916a9c0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key keyPath.'

I have checked all the connection in connection inspector ,those all are clean. Please suggest some solution to overcome this problem .

Answer 1

This is normally related to a deleted IBOutlet. Check your Storyboard/Nibs outlets and see if there anything marked with an "!": it means the corresponding outlet was removed.