HTTP status code 203 means the server successfully processed the request, but is returning information that may be from another source. Not present in HTTP/1.0: available since HTTP/1.1
The returned metainformation in the entity-header is not the definitive set as available from the origin server but is gathered from a local or a third-party copy.
The set presented MAY be a subset or superset of the original version. For example, including local annotation information about the resource might result in a superset of the metainformation known by the origin server.
Use of this response code is not required and is only appropriate when the response would otherwise be 200 (OK).