Send iOS push notifications from two apps, but only have one get delivered if user has both apps

Question

If a user has two of my iOS apps installed (say, a free and a pro version) and I want to make an announcement to all of the users that have either app installed via a push notification, is there a way to prevent two notifications from being delivered to a user if they have both apps installed?

In iOS6 and lower it seems like the push notification token was identical between apps, so it could be used a unique identifier to make sure only one notification was sent to someone. However, as of iOS7 it seems like this was changed so that the push token is unique per app.

Additionally, I do not have any other unique identifiers for a user (such as their email).

The answer to this question might very well be "No". But if that's the case, any references you could cite to support your conclusion would be helpful.

Answer 1

Turns out this is possible after all.

iOS has an iosIdentifierForVendor property which returns a unique identifier for a user tied to the vendor of an application. This can be used to determine if a user has more than one of your apps installed, and thereby only send them notifications from one app.

Answer 2

Remote notification token should be identifier per App, please make sure your free and prod use different App ID, and they will register different token.