yes you will. even though your contract gets extended, your upgrade date stays the same until you purchase a phone. In terms of your data plan, yes you can keep it, but depending on where you get your phone (authorized retailers), you may have to call AT&T to have them change it back. When you change phones it always prompts for the new data plans, and some retailers don't have the ability to convert back to your unlimited. But it's just a simple call to AT&T and they can do it for you.