Over the years, Apple refused to offer more flexible pricing options to developers. There never has been (and may never be) such a thing as “upgrade pricing” in the App Store, unlike on more open platforms like the Mac. Developers either had to offer major new versions for free, charge current users the same amount as new users, or try to jerry-rig an in-app purchase system.
One, you can't say "jerry-ing". Look it up.
Second, why can't we sell subscriptions to "Vol. 1 of My App"? That is, are subscriptions necessarily time bound?
Luckily, it doesn't matter. It's always seemed to me that there's got to be some slick way of having features unlocked based on your purchase date and which in-app purchases you've purchased later. Why can't you sell "v2 features" as a $10 in-app purchase? The only thing stopping you (and this is a complaint I've seen) is that your app has to support both versions.
That is, if you don't want to change the SKU (TIL: "stock keeping unit" -- add fuel to my earlier The iTunes Warehouse And Dollar Store), you have to have both a version 1 and a version 2 in the same app bundle.
Sorta. If you don't think of it as a weird mutli-headed creature (if no pay, display v1; if yes paid, display v2 <<< bad/dumb), but as your new creature with crucial [new] features behind a paywall, you're done. Who cares if, a few versions in, you save some dev time by allowing the people who paid for v1 get a few v2 features even though they haven't paid for that or your new version 4? They weren't paying, so it's not really a revenue loss.
And that, surprise, exactly what Overcast, Castro, and Fantastical (a few places I've paid and gotten bonus features in new, subscription based versions) have done.
From The Verge's review of the new Fantasical:
If you already own Fantastical 2, though, Flexibits has a pretty cool offer to help mitigate that feeling, in part. If there’s any feature in Fantastical 2 that is now a Fantastical Premium feature, you will still be able to use that feature in the updated app on the platform you own it on, even without a Premium subscription. You won’t need to sign up for a Flexibits account to keep that functionality. And Simmons tells The Verge you’ll still get free bug fix updates as well.
See? Who cares if the people who weren't going to pay the new price get some bug fixes? That's free for them, but it's also essentially free to you -- there's no price to send out that bug fix to more people for app store apps.
And I say this as a Fantasical 2 owner -- for iPhone. I had the iPhone version on my iPads too (no reason to pay twice to get an iPad specific UI, though I considered it), and then, poof!, one day the last week or two it upgraded on my iPad to a full iPad UI! That was a surprise.
At first, I was a little peeved, since I actually liked the old iPhone UI on my iPad, especially my iPad mini (which is old enough I still have to use 2). iPhone UI on iPad was ugly, but tres functional. But now I get the new UI... and liking it after my "free iPad UI exposure" means there's some new advertising too.
Thanks to the "free" upgrade, I know that I could spend more to get a potentially fancier experience. I probably won't, but they've lost almost certainly exactly zero dollars (and lost exactly zero good will; they've probably even built a little) giving me part of v3 in my v2 for free.