Question [Q] No HDMI out?

Hi,

I have a Xperia T and there is a new custom rom out for it which is the Omni rom (KitKat) and it says "Known issues, No HDMI out" . I would like to know what no HDMI out actually means, Does this mean my camera will not function? Does it even have anything to do with the camera? Just need an answer to this before I go ahead and try updating the phone to the Custom Rom.

Thank You!