But Apple is showing how they want paid upgrades to function. They removed the previous version of Bento from the App Store and replaced it with Bento 4 as a new purchase.
I think this is pretty much correct. But it also highlights the biggest problem with this “Tweetie 2” approach: how are customers supposed to feel who just bought the previous version and are now being asked to pay for the latest? There’s no infrastructure in place to, for example, give the latest update for free to anyone who bought the previous version within the last few months.
The other problem with this approach is that it makes it impossible to issue bugfixes or other minor updates to the previous version without making it available for sale publicly, which would lead to some new customers inadvertently purchasing the old version and being quite unhappy about it.
The real message from Apple is clear: “Design or adjust your business model such that it doesn’t need paid upgrades. Look, here’s a great in-app purchase system. Find a way to use it.”