I would like to release a new version of our app. and due to the size of the project we have decided to release a new app rather than update our current one. We would like to offer a discounted price to user who already own the current version
Example: Joe owns version 1, when version 2 comes out Joe only has to pay 75% of the price to get the new version. Bob didn't have version 1 so to get version 2 Bob pays full price.
Can this be done automatically or through discount codes?
It can't be done at all, either way. There's no way for the App Store to offer discounts that are linked to the sale of another app.
Try using an app bundle, instead. May require pre-existing configuration, so check first.
You can update the old app so that it writes something to a jointly held space on the keychain, in a file or on iCloud. Or you can add a canOpenURL to the old app. Then in the new app have some stuff that the user gets to do either by having that old app on their device or by buying an IAP.
