Apple requires this certificate be renewed every 365 days. The process for renewing the Apple Push Certificate is essentially the same as creating a new one. The critical difference, however, is that the existing certificate must be renewed, and re-uploaded into Dashboard. If a new certificate is created, on the other hand, currently enrolled iOS and macOS devices will appear offline and be unable to receive MDM commands unless they are re-enrolled.
https://documentation.meraki.com/SM/Device_Enrollment/Apple_MDM_Push_Certificate