T-Mobile just announced its new JUMP! upgrade plan (no more caps after that, I promise), and it's really, really different. Really, really. As far as I am aware, no other mobile network in the world has a smartphone upgrade plan like this. If you haven't already read about the basics on Jump, let me break it down for you.
Jump allows you to upgrade your T-Mobile smartphone on one of the carrier's new Simple Choice plans every 6 months.