I have been running my 5900X at 240/160/190 +200 for about a year and a half with my B550-XE, which is basically a B55 DH.
No problems.
If your CPU is new, like made in the last year.. its probably best to stick with the newest AGESAs.
My 5900X is near launch, and these newer AGESAs suck for it, so I am using an old one. All the voltage, all the boost..