They use a URL Scheme to check for the existence of previous versions on the device, and depending on the result, offer one of three in-app purchase prices for

They use a URL Scheme to check for the existence of previous versions on the device, and depending on the result, offer one of three in-app purchase prices for the same result: activating the new version. See also http://www.macdrifter.com/2013/10/an-interesting-ios-app-store-upgrade-example.html http://www.macdrifter.com/2013/10/an-interesting-ios-app-sto...