When the transmitter receives a POST request, it MUST verify that the request includes the "Content-Type: application/vnd.ms-wmdrm-extended-operation-request" header. The presence of this header indicates that the entity body of the POST request contains a revocation list request message.
The transmitter MUST process the revocation list request, complying with the rules defined here. Unless there is an error, the transmitter MUST include a revocation list response message in the entity-body of the response to the POST request.
The response to the POST request MUST include a "Content-Type: application/vnd.ms-wmdrm-extended-operation-response" header. This indicates that the body of the response contains a revocation list response message.