updating kindle book
You commented that you can update a kindle book by resubmitting the modified copy from your kindle account, but, do you know how a purchaser can be sure to replace their old copy with the revised copy?
(a brief history of timelessness)
It is my understanding that you just delete the old version from your Kindle and download the new version; however, there is a lot of talk on the Kindle forum that it is not working for everyone.
I think we need to do some more research. Sorry if that is not helpful.