[rdsnsca]

Bundles can be used for upgrade pricing, you put the new version up for full price (ie. $20) and and a bundle with the new and old version (ie $30, for a 50% discount on it) for those who own the old version. When you buy a bundle you don't pay for the one you own.

[gcr]

Are there any examples of apps that do that? As a consumer, I haven't ever heard of an app that offers this (e.g. goodnotes, LiquidText, MarginNote, Audulus and Things have new major releases and don't seem to do this)

[refulgentis]

Couple of the old school macOS dev houses tried this once this hack became visible and little birdies said the hack WAI. (ex. OmniGroup)

Since then, people have backed off.

If you're going to this much work to help users workaround Apple nonsense, you really care about helping them save money, and the support + refund costs of people accidentally buying the bundle with the old version they don't need is > just building out your own server-side system, versus a combinatorial explosion of bundles in the App Store that creates a confusing minefield for users.

[refulgentis]

By jumping through hoops, tying unrelated tools together, confusing users, and reaping an extra $10 you didn't want to take + support costs thereof, yes, it is possible. It is not what we expected or asked for when we started asking for this in 2007 (we = iOS devs).