>D) Remove the app from sale and submit a new app. You're wiping your slate with links, app reviews, etc. You also lose customers, who don't find out about your

>D) Remove the app from sale and submit a new app. You're wiping your slate with links, app reviews, etc. You also lose customers, who don't find out about your shiny new version Um, how about this: Since your encoder is 100% faster you obviously did some substantial engineering on it. So why would this be just an update to the existing app? Even if you could charge for it? The easy option you didn't mention is: F) Keep the old app in the store and start selling your "Encoder2" as well. "But I wrote 'customers don't find out about your shiny new version' you are now thinking" Well, you know there is the option of having users of the old app being notified about your new offerings, right? Don't tell me you have never seen such a popup in an app telling you about that companies new app. So now you have two apps in the store and it is up to you to make sure how they differ and how the new one is an improvement over the old one. Now the customer has the choice which to get. For them nothing changes.