[NeoTar]

> It's a book, not a web page!

That's a distinction you are making - that books cannot or should not be updated, whilst web pages can/should be. It's no longer intrinsic to the nature of a book as a digital text.

Perhaps a list of heads-of-state is a silly example to use, but a text-book may be a better example - in a digital world it may be a reasonable expectation that a text-book would be 'correct', and so receiving updates would be appropriate. Or a particle physics data-sheet, where an updated value for the mass of a particle could be included.

Of course this should be consensual - "The publisher has provided an update to this text. Please accept, reject or review the changes", and it would be great if e-books and readers had a mechanism to scroll back and forward through editions (but perhaps that is a pipe-dream).

> I have old astronomy books that indicate the visual appearance of Mars changes due to seasonal vegetation! This was obviously updated in later editions; the old edition remains as an important historical record of what we once thought.

That's pretty much what I said in my comment. Sometimes the historical context is important, valuable or interesting.

[cxr]

> it may be a reasonable expectation that a text-book would be 'correct', and so receiving updates would be appropriate[...] Of course this should be consensual

It is implicitly consensual—when the consumer chooses to buy/download the newest edition. Don't try to "change" what's an an ebook, though. (Not that it's even possible.) Make new editions available if you want and allow the reader to decide whether to go for them. Otherwise, it is not consensual.