Starting January 1, 2026, developers in South Korea must implement a server-to-server notification endpoint when using Sign in with Apple. This endpoint enables Apple to send crucial updates about user account statuses, including email forwarding changes, account deletions, and permanent account deletions. These notifications are essential for maintaining data privacy and user control within the app. Developers must promptly update associated data and server infrastructure upon receiving these notifications. Before submitting or updating apps, developers should carefully review the account change guidance provided. For email forwarding changes, updates must accurately reflect the user's preferences within the app's data. Developers should offer clear guidance for users to complete email address verification. In case of account deletions, developers should adhere to specific guidelines detailed in TN3194. Developers are responsible for complying with all relevant legal requirements concerning user data storage and handling. Developers should seek legal counsel for any uncertainties regarding legal obligations.