title: Apple Push Notification Service - Multiple device tokens are valid for the same device
body: <p>In order for us to send users iOS notifications the following flow occurs: a user installs our app, registers with APNS, and sends the registration token to our server to be used later to send notifications.</p>
  
  <p>The above process is repeated for every device on which the user installs our app; we'd like them to get notifications on all their devices.</p>
  
  <p>In addition to this, the process is repeated when a user uninstalls our app and reinstalls on the same device.</p>
  
  <p>Every time the process repeats we get a new, distinct registration token. This is all well and good however, we noticed that only recently when our app is uninstalled, the device token remains valid after it is reinstalled and a new token is generated. It is our understanding that a single unique token can exist for a device.</p>
  
  <p>Apple's documentation seems to suggest this as well (<a href="https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html#//apple_ref/doc/uid/TP40008194-CH100-SW12">https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html#//apple_ref/doc/uid/TP40008194-CH100-SW12</a>)</p>
  
  <blockquote>
    <p>The form of this phase of token trust ensures that only APNs generates the token which it will later honor, and it can assure itself that a token handed to it by a device is the same token that it previously provisioned for that particular device—and only for that device.</p>
  </blockquote>
  
  <p>When a new token is generated after reinstall and sent to our backend, we've got two device tokens that point to the same device and as a result we send multiple notifications to that device. Are we misunderstanding the documentation? If so, what's the typical way of dealing with the reinstall scenario?</p>
  
  <p>Thanks!</p>