Hey Todd,
Likely, there will be a few displays claiming HDMI 2.1 support at CES 2019 next week, it's very unlikely any of them will support 48Gb/s, so true HDMI 2.1.
The HDMI 2.1 h/w upgrade for the X8500H isn't expected until July 2019, and AFAIK there is no consumer product offering a 48Gb/s...