Perfect armor for dungeons

so i checked wiki and it says that dungeonized perfect armor requires cata 7 to use, and i thought (prob from a video) that its cata 24 or something like that. so whats the actual requirement and how viable is it for a tank (i have dungeonized old drag armor rn, and idk which would be better for ehp)

and btw why isnt mastiff armor used in dungeons? bc it seems really op, so the only downside i see is that its not dungeonizable