My app saves the numbers people enter in fields in the NSUserdefaults for when they exit and return to the program. My next update is fairly significant and some of the fields have been moved around to different views. I'm concerned that reading in user defaults from version 1.0 will cause some initial flakey behavior. Is there anyway to have an update do a "clean" install? Is there a setting in the info.plist or something? Basically I want the app to be deleted and then installed to remove all the old data.