iOS - Renew APNS distribution certificate

Question

As far as I know I can renew the APNS by creating a new certificate and finally update my server to use it.

But, I don't understand what happen if I have two APNS distribution certificates both non expired yet at same time. What will happen with devices that used the older certificate to generate the token?. Will they stop receiving push notifications? What is the best approach to face a renew APNS certificate?

In my server should i handle both certificates too? I mean, when I establish a connection with Apple servers I can use only one pem.

I have already read:

How to Renew Push Notification Services Certificate

Renewing Production Push SSL Certificate - Apple APNS

Answer 1

devices that used the older certificate to generate the token

Devices do not use the certificate, the certificate is used only by the server. Therefore there is no such thing as tokens obtained from a device using the older certificate.

(Devices use a profile with push entitlements in order to obtain the token,and this does contain a certificate however this is not the same thing as the certificate used on the server).

Therefore your server just needs to use the new certificate when communicating with the Apple servers and your apps will continue to receive pushes, providing you have generated and are using the correct certificate (i.e. development for the Apple Sandbox server and production for the Apple production Server).

Incidentally a single .pem can contain multiple certificates if desirable.