About Apple policy for in app links

I have read on an article that Apple is applying a policy by which an app can't promote selling another apps, but i dont know the exact details of this. What about a DEMO version that haves a link to the store for the full version? can this still be done?.

If anyone haves more precise information on the subject开发者_如何学C i'll appreciate it.

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You are just not allowed to offer services (in app currency or similar) for app downloads.
You won't have a problem with a link to the pro version in a lite version.
You won't have a problem with a "My App Store" link that shows all your apps either.

Don't reward your users for downloading other apps and you should be good.