We don't know as this option has not been presented to dealers. There is a technical note that explains replacing the HDMI board to bring older UHD722 units up to the latest available Meridian spec shipping in current UHD722's.
When doing so there is actually an 8th HDMI input that stays tucked inside the UHD722 box. There are some power supply issues with other manufacturers products which can complicate swapping out a HDMI board to upgrade to HDMI 2.1.

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