3840 and 2160 are common numbers around this site or at least they have been over the last half year. You might be surprised to find we have been on the 4K bandwagon since 2011 when Ryan was given some time with the EIZO DuraVision FDH3601 at a vendor presentation. Sure, that $30,000 behemoth was designed for medical imaging and air traffic control stations, but it can run DiRT 3 like a champ. But, even now, 60Hz at those resolutions require at least two cables working in unison.
HDMI 2.0, recently announced, has been designed to achieve single-cable 4K at 60 progressive frames per second.
The specification maintains the same cable configuration as HDMI 1.4. Devices which support HDMI 2.0 can be connected, at full functionality, with standard "category 2" (marketing term "high speed") cables. Currently available "high speed" cables will not need to be replaced. The devices, on the other hand, must support the higher standard but that only makes sense because… well… why would you need the cable, otherwise?
HDMI 2.0 drives a higher frequency, 600MHz up from 340 MHz, to deliver substantially more bandwidth, 18Gbps up from 10.2Gbps, than HDMI 1.4. The extra bits can be used for 32 channel audio at 1536kHz sample rates as well as the aforementioned 2160p/60 video link.
A helpful feature for many home theater enthusiasts is "dynamic synchronization of video and audio streams". To my understand, this means that end-users will not need to fiddle with latency settings on their speaker systems as the devices will properly negotiate the delay themselves.
I have not been too much of a fan of HDMI licensing requirements and restrictions, but this release is definitely major version-worthy. The compliance test is expected in late 2013. The devices, however, are what most of us care about and, well, that depends on those manufacturers.