My design would be HDMI 3.Y where Y is a variable-length Base32 encoding of the value of a bitmask representing the presence of the underlying features of an HDMI port/cable/device.
Fret not, consumer! Just install the HDMI™ Companion App™* for easy parsing of the version numbers.
*HDMI™ Companion App™ and facial recognition are required for decoding of 4k HDR content on your media devices.