The MoreAvailable element is an optional child element of the Collection element in Sync command responses that indicates there are more changes than the number that are requested in the WindowSize element (section

All elements referenced in this section are defined in the AirSync namespace.

Command request/response

Parent elements

Child elements

Data type

Number allowed

Sync command response (section

Collection (section



0...1 (optional)

The MoreAvailable element is an empty tag element, meaning it has no value or data type. It is distinguished only by the presence or absence of the <MoreAvailable/> tag.

The MoreAvailable element appears only in responses that are sent from the server to the client. It appears only if the client request contained a WindowSize element and there are still changes to be returned to the client.

The server includes the MoreAvailable element in Sync responses that contain no additions, changes, or deletions when the server encounters elements external to the protocol.<10> If the client receives multiple Sync responses that contain the MoreAvailable element and fewer changes than requested by the WindowSize element value included in the Sync request the client SHOULD continue to send Sync requests to retrieve additional changes until no additional results are sent by the server, but MAY stop sending Sync requests if the Sync request and response loop is affecting network performance and synchronizing the client is of less importance than network performance.

The MoreAvailable element has no body. It is omitted if no additional changes are available. The maximum value for the WindowSize element is 512. The server interprets WindowSize element values above 512 and 0 (zero) as 512.

If the WindowSize element is omitted, the server behaves as if a WindowSize element with a value of 100 was submitted. The MoreAvailable element is returned by the server if there are more than 512 changes, regardless of whether the WindowSize element is included in the request.

Protocol Versions

The following table specifies the protocol versions that support this element. The client indicates the protocol version being used by setting either the MS-ASProtocolVersion header, as specified in [MS-ASHTTP] section, or the Protocol version field, as specified in [MS-ASHTTP] section, in the request.

Protocol version

Element support