Hello, I own an iPad 3 (16GB) and it still runs fine, and hopefully for the 2 more years of college. However, what would happen if my iPad couldn't run the latest iOS version down the road, would I still be able to download previous apps that I paid for? In other words, take Keynote for example. It requires iOS 7 to run, but an iPad 1 couldn't run the latest version. IF this person purchased it before and deleted it, can they redownload the latest revision of that app?