Ok, thanks! That's in line with what I was expecting.
Currently, I have it so that the "book details" page in the users library links to an "order" page, that displays if a new version is available, and gives you the option to update the book. Ideally, I would have the ability to update the book directly in the "book details" page, but for now I think this should suffice.
If you have any ideas or feature requests for an ebook store, I'm would love to hear your thoughts! Things that annoy you about the Kindle store and would like to see done differently, etc.
-Jacob