Today we received an email from Apple:
Dear XX XX,
On March 29, 2021, token and certificate-based HTTP/2 connections to the Apple Push Notification service must incorporate the new root certificate (AAACertificateServices 5/12/2020) which replaces the old GeoTrust Global CA root certificate. To ensure a seamless transition and to avoid push notification delivery failures, verify that both the old and new root certificates for the HTTP/2 interface are included in the Trust Store of each of your notification servers before March 29.
Note that Apple Push Notification service SSL provider certificates issued to you by Apple do not need be to updated at this time.
Learn more about connecting to APNs.
If you have any questions, contact us.
Best regards, Apple Developer Relations
How to proceed if we are using FCM for push notifications? FCM needs to update their certificates?
I am new to all this (FCM, APN, iOS development), so, a full explanation would be great.
There's nothing you need to do about it in your case, because you aren't the one running the push notifications provider.
If any changes needed to be made for other things Firebase will send you an email on how to do it.