An expiry date has been set to the DNSSEC signature (RRSIG), and you need to update it periodically. In addition, we also increase security further by periodically updating the key (DNSKEY) used for the signature. Although DNSKEY and RRSIG are not displayed on this service’s Record Management screen, they are actually included in a zone as other records. Through such periodic updating of DNSSEC-related records, we record zone update histories with the comment "DNSSEC Operations" for "system" as the operator and Zone Application History with a log type called "Update record."