With the iPhone 6 announcement being a huge hit yesterday along with all the new features, it's safe to say that Apple made a pretty substantial improvement since the iPhone 5S. That being said, if you're looking to upgrade and check what your eligibility is, we've got the perfect solution for you. All you need to is text or call the corresponding number below for whichever carrier you're with and a notification should be sent to your phone that includes all the details. At the moment we do know that AT&T Next allows you to upgrade every 12 or 18 months depending upon which plan you went with, so some AT&T users may just be in luck. But without any further to do, check out the list of numbers below to check your upgrade eligibility.