With the upcoming official release of iOS 14.5, iPadOS 14.5 and tvOS 14.5, all apps must use the AppTrackingTransparency framework for the user to track them or access their device’s ad account. Unless you get permission from the user to enable monitoring, the device ad price will be zero and you will not be able to track them.
When submitting your application for review, any other tracking method – for example by name or email address – should only be announced and approved by AppTrackingTransparency in the App Store Privacy Information section of the product page. You will need to include a purpose string in the system query to explain why you want to track the user in accordance with App Store Review Guide 5.1.2 (i). These requirements apply to all applications beginning April 26, 2021.
As a reminder, collecting device and usage data with the intent of extracting a user’s unique representation or fingerprint continues to violate Apple developer program license agreement.
Learn about user privacy and more Data usage