Originally Posted by Stefx
Today (Kindle) and yesterday (Kobo) both those apps released a new version with the in-app store removed.
It's an annoyance (albeit minor).
Is it a reaction to an Apple policy?
Yes, Apple are requiring apps to either offer in-app purchasing using Apple's system, for which Apple takes 30% of the price, or remove ways to buy from within the app, and remove links to ways to buy from outside the app.
You can still buy books from Amazon/Kobo websites and the books will still sync to your iPad and you can read them fine, the apps just can't have the Store link in them any more.