Update in-app purchase content for iOS app?

I can't seem to find an answer to this question anywhere, so here goes...

I've developing an iOS app that will have non-consumable in-app purchases (expansion packs). Say I sell a pack that has 10 levels in it, for example, and in a month I want to update that in-app purchase to have 15 levels. The user will NOT have to re-purchase the pack; they would just need to update it.

Three questions:

1. Is this even possible?
2. How are users notified of this (or how SHOULD they be notified of th开发者_StackOverflow社区is change?)
3. Does Apple need to review changes like this?

Thanks in advance, Rick

1. Clearly yes. It is up to you, to write the code in a way, that your app remembers which updates a user has bought and how these updates are interpreted in your app. The only thing that will stop you from changing an in-app purchase content is when you take functionality or in your case levels, away again. Apple won't allow you to upload a new paid version with less functionality.
2. I would probably tell the user in the info text you have on the app-store, that they will receive 5 additional levels if they already have the 10 level upgrade.
3. Apple reviews every change you make to the app when you upload a new version to the app-store. This is true for any feature as it is for updates to in app purchase.

I did something similar to this in my app recently. I was saving a BOOL value in NSUserDefaults that specified if the user had purchased the expansion pack. In my update I simply had the change the code that was given to the user based on whether or not that BOOL value was YES or NO. As long as you designed it correctly you shouldn't have any troubles updating

1. Yes it's possible. Provided you keep a track of who has bought what pack (ie. keep a bool value as an NSUserDefault), then they will still have access to it (even if you add more stuff/levels to it).
2. It depends what you mean by notified; they will know if they read the update comments when they install the update. Also you could just choose to alert them when the load the app after the update - your call.
3. If you're submitting the code Apple will review it. Just think of it like any other update to an app.

Hope this helps!