Most .daz files saved after 2.0 will open in 4.5+ (No difference between 4.5 and 4.8 for this statement.) There are some versions of DS after 2.0 (some of them are certain versions of 3.0) where they will not, but that is not as prevalent as you have been told.  No I don't recall which particular versions, and AFAIK, nobody wrote them down, though most of the problematic versions of .daz files don't open in 4.0 or later versions of DS 3 either.