Card updater is the short, informal name for a card account updater, the network service that keeps merchants' stored card details current, and that entry describes how it works.
Cards are replaced regularly when they expire, are lost or stolen, or are upgraded. Merchants that keep cards on file for subscriptions, instalments or one-click checkout would otherwise see payments decline until the customer re-entered their details. With an updater, issuers report changes to the card network, and merchants or their acquirers receive the new number and expiry date, either by checking their stored cards in batches or by receiving updates in real time during authorisation. Updaters also report closed accounts, so merchants can stop trying to charge them.
Each major network runs its own version, such as Visa Account Updater and Mastercard's Automatic Billing Updater, and "card updater" covers them all. The service supports recurring card transactions and complements network tokenization, which updates stored credentials automatically.