APN Device Token for Multiple Users

Question

I have read apple's push notification guideline and a few stack overflow questions such as these:

• APNs duplicate tokens
• Are push notification tokens unique across all apps for a single device?
• What Happen If a APNS Device Token Expired?
• Does the APNS device token ever change, once created?

and even considered using google's GSM but realized underlaying it uses APN

• Google/Apple Push Notification Service (APNS/GCM)
• Is there any reason to use Google GCM vs Apple messaging for push notifications?

but none point out what happens when there are multiple users created for an app on the same device or when one user has multiple devices. And only the question "Are push notification tokens unique across all apps for a single device?" addressed the multiple devices case but the answer was 5 years ago, so was wondering if anything changed with iOS 9.

Does that mean my server(provider) will have have a one to many relationship with a token and the primary key will constitute a user_idand a user_token?

Answer 1

Based on the reading material linked in the question, and Apple's documentation that the token may change, the user_id and user_token will have a many-to-many relationship and we should use Apple APN feedback service to remove old tokens.