I’m delighted that Apple’s iBooks app can display an update badge to alert you when a book that you have purchased from the iBooks Store has been updated. It would be more delightful if the alert mechanism worked.
For example, here is what I see at the bottom of the iBooks screen on my iPhone. Looks like I have 32 books waiting to be updated.
However, when I tap the Purchased button, I see a list of every book I have purchased from the iBooks Store, but I see nothing to tell me which of them needs to be updated.
Meanwhile, back on my Mac, when I open iBooks (using the same iBooks Store account as on my iPhone), and then choose Store > Check for Available Downloads, this is what I see:
Looks like the alert update mechanism, like so much else in Apple’s cloud ecosystem, needs some debugging.