We are still very much in the early adoption phase of UHD. If all you are concerned about it more pixels, then you should be safe if the TV has HDCP 2.2 and HDMI 2.0 and you may need a new HDMI cable. If you want the other stuff, then you need at least HDMI 2.0a.
Look at the early adopters of HDTVs that only had analog composite video connections. A few years ago, the new cable boxes, blu-ray players, etc. would only sent out 480p to such TVs. The content providers don't care if early adopters get screwed and can't use the full potential of their expensive TV, they only care about keeping their content safe (or giving them the illusion of it being safe with these extra measures).
I want a new display really badly right now. Next summer I might even have the money to buy one, but I think I will upgrade to some nice dual subwoofers instead. The display market is really in flux, right now and it will likely not be a good time to buy a new display for 2 or 3 years, unless you just want a good 1080p set and not this new stuff we are talking about.
