It supports 4X4 MIMO, but the physical antennas have to be installed by the manufacturer, in this case, Apple would have to be sure to include the antenna set. It is supposedly supported via software update, so it seems that might also depend on Apple.
Anyway to tell if there are enough antennas support 4x4 MIMO?
It's all about the modem here. Big thing is for me: if Qualcamm, what model, X12? How many antennas, 4x4?