Hard Design: Notification System

What is the recommended way to handle a user who uninstalls your app but still has their device token in your database?

— Tests your understanding of this concept.

Answer Options

A Keep the token forever
B Delete immediately on app uninstall event
C FCM/APNS will return an invalid token error — remove token on first delivery failure
D Refresh the token automatically

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This question is from the Design: Notification System topic (System Design Cases).

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