This would be a major release, bumping up the app version to version 4.0. Obviously there are other changes apart from cosmetic ones, but the most noticeable one, at this point in time, would be a refreshed user interface where you can check out a sample of it above. First of all, the redesigned library would ditch the basic grid of book covers, adopting instead a carousel at the top that displays recent items. Other than that, there would also be an expanded navigation panel that has been updated to include quick access to your books, documents, and newsstand periodicals. Definitely a time saver if these are the segments that you tend to pore over on a regular basis.
Do you like what Amazon has done with their native Kindle app for Android?