The proxy service certificate expiring notification. If the time interval cspGcPSCertExpireInterval is positive, and cspGcNotifyPSCertExpiring is 'true', a notification will be issued for every proxy service certificate that will be expiring within this time interval. This notification is issued only once for each of these certificates. If the interval is changed from a positive value to 0, the proxy device will clear its memory of notification issued in the past, and stop issuing new notification. The notification contains the subject name, the serial number and the issuer name of the certificate, the serial number of the issuer's certificate, and the end date on the certificate.