The latest Apple Operating System for Mobile Phones and Tablets has a 74% adoption rating and should climb further in the next few months. Apple is encouraging developers to update their apps to be iOS 7 compliant by February 1st 2013.
Developers who want to submit new apps or update existing apps will have to make sure they are using the latest version of Xcode 5 which includes 64-bit support and access to new features like background APIs. Learn more about preparing your apps by reviewing the iOS Human Interface Guidelines.
Does this mean developers have to rework the graphics and spend a ton of time optimizing their apps for iOS 7? Not exactly. It appears that this requirement is more about the underlying construction of apps rather than their appearance. You can simply just use the new code and API’s without changing anything on the front-end.