Classically, T-Mobile has relied solely on its AWS spectrum — which lies in the 1700MHz band — for its 3G / 4G HSPA+ deployment. It's been observed in recent months that the carrier is starting to use its 1900MHz holdings for HSPA+ as well, a "spectrum refarming" strategy that lets it move to 84Mbps HSPA+ service — and as it has pointed out today, the reconfiguration allows it to move forward with LTE as well.
T-Mobile has never been shy about mentioning the iPhone at virtually every opportunity — it boasts of having over a million unlocked iPhones running on its network, and has said time and time again that it'd love to bring the device onto shelves. With the move to HSPA+ on 1900MHz — which the iPhone already supports — it's pointing out that this means iPhone owners will be able to get true 3G (or, as T-Mobile calls it, 4G) service:
Ray on the benefits of network improvements: "Our 4G network will be compatible with a broader range of devices, including the iPhone."— T-Mobile USA (@TMobile) February 23, 2012
That's big news for unlocked iPhone owners who don't want AT&T, Verizon, or Sprint, but this doesn't necessarily mean T-Mobile will be picking it up officially as an on-contract device. CEO Philipp Humm says that there's "nothing new to report" on whether we'll see a T-Mobile iPhone in 2012, and that they're currently focusing on Android and Windows Phone — the typical iPhone alternatives. He says that they'll need the "right terms" in order to sign a deal with Apple, which is language we've heard from US Cellular before — it's an open secret that Apple drives a hard bargain, and Sprint's financials are a little worse for the wear so far as it seeks to recover the investment of becoming an iPhone partner. Considering the amount of money T-Mobile needs to throw at its LTE build-out right now, sinking large amounts of cash into the iPhone might simply not be in the cards.