It already is on the Z4 and G4 boxes, the G5 box for ultra HD is due shortly*
*No idea how long shortly is as it does keep getting delayed.
Well, many a true word said in jest!
In usual BT form, their shortly turns out to be longer than any dictionary definition and should now be launched in November.
As the addition was mentioned in the price rise letter, I am sure they will tell their customers of the delay and also delay the price rise.