You can run 4K at 30fps on a 1.4. It's not spec'd as 2.0 and 2.2, but it's possible it's just a spec. The hardware itself may be in the unit itself just not functional without an upgrade. This is the optimism in me hoping, but in all likelihood we'll need a new unit. I think this thing was spec'd long before 4K was finalized and it's delays to market resulted in dated hardware. I mean we were hearing about this thing for well over a year.
I'm also a bit concerned that Apple is foregoing picture and sound quality on this in an effort to save bandwidth rather than simply put out the best and most technically advanced product they could. It seems like they simply don't care figuring people will use ATV exclusively to feed secondary rooms in the home and mobile devices where 1080p and 5.1 is plenty rather than make it the main hub for a home theater. 7.1 audio is doable now yet they don't offer it in the media files themselves while other services have moved on. Further, they have made a mess of 5.1 with some sort of bastardized signal processing.
The other problem is they don't participate with the entire digital copy environment (UV) so a lot of physical media purchases need to be duplicated in iTunes to complete a collection. We don't use ATV in the theater because all streaming is garbage on a large screen, but it sure as heck would be nice to use it. I mean the whole idea of digital copy was buy physical media, leave that in your main viewing area and redeem a digital copy for your mobile devices and streaming devices in other rooms. They got that down, but then they want to insist this is the future of television. Well if it is the future of television, then you need to participate in the entire digital copy environment and your goal needs to be not to compliment physical media, but to supplant it.
It's a little frustrating, at least for now. They stepped into the videophile room with this thing so I think a lot of demand to keep up will force their hands to improve the product, but there is nothing more frustrating than waiting for your choice of ecosystem provider to catch up with the competition.