# Returned notification information

The `ReturnValue` property returned by `callback` is an array of objects containing the requested notification information on new messages. Each item (object) in the array corresponds to one new message and contains the header information for that message.

Table: ReturnValue properties for notification information
Property | Type | Notes
--- | --- | ---
`<item>.MessageType` | string | Possible values: `"SMS"` `"MMS"` `"unknown"` The Messaging Service only supports SMS and MMS. Other types of messages are `unknown`.
`<item>.Sender` | string |
`<item>.Subject` | string | Since SMS does not support subject, this property contains the first few characters of `BodyText`.
`<item>.Time` | object |
`<item>.Priority` | string | Possible values: `"Low"` `"Medium"` `"High"`
`<item>.Attachment` | boolean |
`<item>.Unread` | boolean |
`<item>.MessageId` | number |