December 12, 2016 announced HDMI 2.0b, can not think of January 2017 again updated.
HDMI Forum in the evening of January 4 published HDMI 2.1 specification, and from December 12, 2016 HDMI 2.0b specifications published, it seems that the interval is quite short; does, HDMI does not want to lag behind DisplayPort too much.
Looking back at HDMI 2.0b, it supports HDR, 4K @ 60Hz, 21: 9 hardening and 18Gbps bandwidth.
HDMI 2.1 finally supports 4K @ 120Hz and 8K @ 60Hz (see these two figures is really happy), as already in the use of the DisplayPort 1.4a early support ... while HMDI 2.1 also supports dynamic HDR (High Dynamic Range Imaging, high Dynamic range imaging) and 48Gbps bandwidth. Well, at least 48Gbps bandwidth than DisplayPort 1.4a 32.4Gbps.
The more specific part is that HDMI 2.1 supports eARC (HDMI provides briefings refers to the audio format), but in the past ARC content in the HDMI organization refers to the Audio Return Channel, which is the audio return channel. In addition, HDMI 2.1 supports VRR game mode, used in variable update frequency, in order to reduce the screen tear situation.
HDMI 2.1 is backward compatible with HDMI 2.0 and HDMI 1.4, with no change to the port section.
HDMI Forum is expected in the second quarter of 2017 officially released HDMI 2.1 specifications.