It requires a little hardware mod near the HDMI socket, the pin layout and chips are present just not hooked up, probably so they can feature it as a new feature on the next model. It's also already enabled in the software but hidden.
For a small fee I can add the absent wiring and enable the software. You do need to send me your Retina MacBook of course so i can do the procedure.
PM me for details and address.
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