Reviews are important but they need to accurate. Personally I also feel that reviews have DUTY OF CARE to update an existing review if a book by an author is UPDATED. As an example, I’ve UPDATED my first ever novel by having it PROFESSIONALLY EDITED. The reviews (well the 1-star reviews at least) DO NOT reflect that and the reviews make out the book is still bad grammar-wise.
I suggest that MY READERS re-download e-books bought from me at least every couple of months because then you are ASSURED to always have the LATEST version in your possession. DO NOT rely on Amazon to do this update for you!!!