Updated Certificate for Game Center Authentication
September 13, 2019
A new certificate for server-based Game Center verification is available via the publicKeyUrl property of generateIdentityVerificationSignature. The previous certificate will no longer be available as of September 17, 2019.
Make sure your app always retrieves and uses the current publicKeyUrl value so it automatically uses the new certificate. If your app caches the certificate or hardcodes the certificate URL, it will require an update.