Xcode has evolved rapidly in recent years, and despite stepping through five major releases in less than two years, it is still known as version 4. In this chapter, you’ll learn how to work with projects created in older versions of Xcode and how to update your projects to use the latest features of Xcode and Objective-C.
It is a fact of developer life that at some stage you will inevitably have to dig out an old project and do more than just gaze longingly at it. Maybe you want to make a simple bug fix to an application that was created using a much older version of Xcode. Or you might want to revitalize your app and give it a complete overhaul for the modern age.