/mcpAdmin User API Cisco Unity Connection 12.5 SU3 and later, supports Admin User API. Administrator can use this API to create/update/delete/fetch the users who does not have mailbox using Admin User API. Various attributes of user without mailbox, for example first name, last name, display name, alias, time zone, language, password, roles, password settings, can also be updated using this API . Listing Admin Users without Mailbox The request can be used to fetch the list of all users without mailbox. GET https://<connection-server>/vmrest/adminusers The following is the response from the above GET request and the actual response will depend upon the information given by you: Cisco Unity Connection Provisioning Interface (CUPI) API 165 Cisco Unity Connection Provisioning Interface (CUPI) API -- User Management API Admin User API