My carrier supposedly supported it from day one, but it's a giant fail really. The iPhone *says* LTE all the time, but subjectively the speeds are the same and the signal strength is actually a lot worse.
I used to have normal, three to four bar 3G service when sitting in my office, now it *says* LTE but I get one bar or no bars. So all LTE means to me is that I have to leave my office now to make a phone call.
Plus we all have to get used to stupid DOTS now instead of bars. Because Ive.