What is DisplayID?

In plain language

Classic EDID is 128 bytes, usually with one extension block on top, so 256 bytes in total. That was plenty when a display had a handful of resolutions. A modern 8K panel with multiple HDR formats, VRR ranges and DSC support has far more to declare.

DisplayID 2.0 is the newer structure for that information. In practice you meet it as EDID data that is 384 bytes (three blocks) or 512 bytes (four blocks) instead of the familiar 256.

Why it matters in your setup

Any device in the chain that handles EDID has to be able to read all of those blocks. A device that only reads the first two will silently truncate the display's capabilities — and the source will never hear about the modes that were described in the blocks that got dropped.

What the DR HDMI 8K does with it

DR HDMI 8K firmware 1.3 added support for 384-byte and 512-byte EDID in copy-TX-sink mode; firmware 1.4 extended it to the ten custom EDID slots and to AutoMix, and added the ability to retain DTD data; firmware 1.5 fixed two-block EDID reading of the sink. If you own an 8K display, running current firmware matters.