yeah there is a new one coming out so you cant get the old WHO unless you get it used, the kicker is the WHO really wants to stop publishing these path books so it is likely the new edition will never come out. Fortunately, the AFIP may print a new version of their tome on the subject...
I just read the first 200 pages of the new book: Blood and Bone Marrow Pathology and am quite impressed even to the point of telling you all:
I think I would even put this book in my hemepath top 3.