Free iOS in app purchase for some users/devices

Question

I would like to build a mechanism to free my in-app purchases for some of my VIP users devices. My idea is I pre-save the UDID of the user devices in my backend server. When the app starts, it will call my server and get the list of udid and check if the device is in VIP list. if yes, directly show full features without any button to ask for in-app purchase.

However, UDID cannot be used anymore. What should I do in this case? I dont want to ask user to enter some codes. because it would disturb my user interface.

new updates of the question:

The purpose is that , I got a list of people that they will review my apps , but i dont want to have any pop up to ask for promo code or any specific UI for these people. So my idea is I ask them to give me their UDID (or whatever number that they can identify themselves for their phone), and I save them in my backend. When they download the app, the app call the backend and compare their identifier number/UDID, see if they are my VIP, and give them full features automatically without asking promo code and any UI specific for these user.

I would like to identify the user only. Do you guys have any solutions? thanks

Answer 1

You could do something like provide a URL to the users which opens the app and gives the app some parameter(s). When the app receives these details it could show an alert to ask for a name or some other info (like an e-mail address) from the user. Then you can send the details to your server for verification and set some value in the app to enable the features. In this way the UI of the app is not changed.

Answer 2

I think it's not conform with the iOS/App Store TOS (to be clear).

The easy way is to use the UDID but we can't now... You can get another unique "number" for identifying the device like the Mac Address (you can get in in Objective-C, not really simple but you can).

Answer 3

You can add a button which asks for a promo code (maybe the same button to buy the in-app upgrade). Only those who have a promo code can get the upgrade for free.

Also, should it be "VIP users" rather than "VIP user devices"?