Digital Europe have announced a logo and minimum specification for UHD:

The display device accepts UHD input via HDMI [2.0 according to appendix]

It shall support HDCP 2.2 Copy Protection

• a resolution of 3840 x 2160 pixels
• at frame rates 24p / 25p / 30p / 50p / 60p
• with a minimum supported bit depth of 8 Bit
• at a chroma sub-sampling rate of 4:2:0 for 50p/60p and 4:2:2 for 24p/25p/30p
• with minimum supported colorimetry according to BT.709

PDF including specification and logo information.