Paid Upgrades →

There needs to be a way to make Version 1 no longer for sale, but still available for customers who already bought it. They should be able to re-download the version they bought at any time. Developers should still be able to release updates to that version.

Developers should be able to associate the new version of the app with the previous version. Some sort of logic in the App Store that says, “If you purchased previous version of ‘My Cool App’ then you can buy this version for ‘x’ amount” (where x is the discounted price). And if not, then you buy it for full price.

Yours truly on Mac Appstorm about paid upgrades. Go read it all.