Interestingly, it first showed up as ROMED8-2T R3.00 and then got renamed to ROMED8-2T/BCM; you can see it’s marked “REV. 3.00” on the board in the pictures. Separately, I’ve seen two reports that ASRock Rack Europe Support has told people that a performance regression with Milan chips was a hardware issue and required a board new revision to resolve.
So far I haven’t been able to get any details on the supposed issue or whether this new version is related. Comments about the X550 integration like this don’t inspire a lot of confidence, but they seem to be replacing the X550 across all their boards, so it could just be a supply change too.
Aside from replacing the X550 with a BCM57416, and dropping the ASM3142 USB-C controller, they appear to have populated a second thermal sensor header.