Google is enhancing the Calendar API with two key features for administrators. A new transfer API is now rolling out, enabling programmatic ownership transfer of secondary calendars within an organization. This API mirrors the Admin console's data transfer capabilities but offers greater flexibility for individual calendar transfers. It allows transfers between users in the same organization without email notifications or recipient confirmation. Additionally, an organization filter has been introduced for the CalendarList:list API method. This filter restricts results to display only secondary calendars owned by the organization. This feature helps administrators monitor ownership status in preparation for upcoming secondary calendar data lifecycle changes. When used with the Admin SDK API's users.list method, it provides a comprehensive list of organization-owned secondary calendars. Administrators can verify ownership using the dataOwner field and make necessary adjustments. These features are available to all Google Workspace customers and do not require admin or end-user controls. The transfer API began rolling out on June 18, 2026, and the organization filter on July 6, 2026.