iPhone - How to transform an iPhone only app to universal app?

Question

how can i transform an iPhone only app to an universal application? EDIT : FOUND SOLUTION If you want to have the "Upgrade current target to iPad" option selected, you must have Target Device Family set to iPhone only, not iPad/iPhone. It works for me!

Answer 1

"The first step is to select your target in Xcode, right-click and use the “Upgrade Current Target for iPad…” command. You will presented with a choice:

Select “One Universal application” and Xcode will do (some) of the hard work for us. The Apple guidelines warn against trying to manually migrate your target though to be honest it is hard to really see why. Also note that if your project has more than one target you can only run the upgrade task once. You will need to check all of your targets and adjust the build and Info.plist settings yourself."

http://useyourloaf.com/blog/2010/4/7/converting-to-a-universal-app-part-i.html