title: SendEmptyPushNotification to gateway.push.apple.com no longer working
body: <p>For at least the past couple of days (maybe longer), nothing seems to happen when I send an Empty Push Notification to at least 1 test device. I'm pretty much using the same SendEmptyPushNotification code as the article posted below.</p>
  <p><a href="https://medium.com/@yangzhoupostbox/part-2-push-notification-for-updating-apple-pass-in-asp-net-6020768d112" rel="nofollow noreferrer">https://medium.com/@yangzhoupostbox/part-2-push-notification-for-updating-apple-pass-in-asp-net-6020768d112</a></p>
  <p>My test device is running iOS 14.4.1. I can manually update the Pass, so the WebServiceURL is working.</p>
  <p>My cert expires later this year. I've rebooted my device. This all used to work and I haven't changed anything.</p>
  <p>NOTE: It looks like the AppleDeviceLibraryIdentifier &amp; ApplePushToken are changing over time. Should these change or remain the same over the life of the Apple device the passes are installed on? I'm wondering if the new PushToken could be the issue. This seems to be the expected behavior. <a href="https://stackoverflow.com/questions/62053307/does-the-device-library-identifier-change-with-the-push-token">Does the Device Library Identifier change with the Push Token?</a></p>
  <p>Does anyone know what might be wrong? Is anyone else having an issue?</p>