The app is definitely more up-to-date. If you own the book (as opposed to using a library copy) you may want to write the changes into the book itself, so the book can be as updated as the app.
You would want to follow the book values, however, if you're using one of the books designed to treat a specific condition. There's a book for pregnant and nursing moms (Eat Right 4 Your Baby) as well as books for Diabetes, Arthritis, Fatigue, etc. Those books have different values on purpose, since some foods are especially healing (or especially toxic) for specific health problems, while still being neutral for the general population with that blood type.