After March 31, 2021 Apple Push Notification service will no longer support the legacy binary protocol and users will need to move to the newer HTTP/2 APIs (Apple's announcement).
If you use PubNub to deliver push notifications to Apple devices, your users will not be impacted. We have taken the necessary steps for our customers to keep the service continuity, so if your application uses APNs with PubNub, we will continue to support you. Our APNs service has been updated to automatically transition to use Apple's APNs HTTP/2 APIs.
NOTE: While we don't expect any impact, in case you experience issues, please contact us at firstname.lastname@example.org for assistance.