iOS guide for app submission
If you are building for the iOS platform and you are using one of our official SDKs the game will be using the iOS IDFA as the user ID for distinguishing unique players. The IDFA is fetched from the client via the AdSupport.framework and as a result you will need to declare it during the submission process in iTunesConnect. Your app must comply with IDFA usage in order to be approved by App Review.
The first step is to answer with “Yes” the question “Does this app use the Advertising Identifier?” in the App Review form.
This will result in opening a new set of checkboxes.
If you are not serving any ads and you only have the GameAnalytics wrapper integrated in the game, you only need to check the second checkbox “Attribute this app installation to a previously served advertisement”. If you serve ads in the game you should consider marking the first checkbox as well “Serve advertisements within the app”.
Note: This does not apply for games using official legacy SDKs with custom IDs or any SDK with the logic for tracking users modified in this regard.
For further readings please visit the iTunesConnect Developer Guide article.