You may recall that HDMI 2.1 offers improved transfer rates and extra features (like variable-refresh-rate support) over previous versions of the format. If you’re properly informed, you may also recall that all of those features, including the improved transfer rate, are completely optional.

The HDMI Administrator says that vendors should

Source: Hot Hardware – DisplayPort 2.0 Ultra High Bit Rate Cable Certification Aims To Avoid The HDMI 2.1 Debacle