I have an iOS app that worked well on all devices in iOS 6.
I recently upgraded my xcode to version 5.0 and tried to build the same app for iOS 7 on an iPhone 5.
Autolayout is a feature of iOS6.0 and later, If you need to support iOS 5, don't use auto layout.
https://developer.apple.com/library/ios/releasenotes/General/WhatsNewIniOS/Articles/iOS6.html#//apple_ref/doc/uid/TP40011812-SW1
Please go through above doc, and check "What's new in iOS6.0" and serach for "Auto layout"
https://discussions.apple.com/message/19879144#19879144