14. A method implemented by a provider in a broadcasting system for updating metadata for multimedia program content scheduled for broadcast in the broadcasting system, the method comprising: receiving by the provider from a client device in the broadcasting system a request for an updated lower fragment containing metadata related to the scheduled multimedia program content, the client device storing an earlier version of the lower fragment in a previously received electronic document, wherein the electronic document has a hierarchical structure based on a prescribed syntax and the hierarchical structure includes an upper fragment located above the lower fragment, and wherein the earlier version is identified by a version identifier; and in response to the request, sending from the provider to the client device an update document having a structure based on the prescribed syntax, the update document including the upper fragment and an invalid element, wherein the invalid element specifies the version identifier of the earlier version of the lower fragment and indicates that information in the lower fragment is invalid.
14. A method implemented by a provider in a broadcasting system for updating metadata for multimedia program content scheduled for broadcast in the broadcasting system, the method comprising: receiving by the provider from a client device in the broadcasting system a request for an updated lower fragment containing metadata related to the scheduled multimedia program content, the client device storing an earlier version of the lower fragment in a previously received electronic document, wherein the electronic document has a hierarchical structure based on a prescribed syntax and the hierarchical structure includes an upper fragment located above the lower fragment, and wherein the earlier version is identified by a version identifier; and in response to the request, sending from the provider to the client device an update document having a structure based on the prescribed syntax, the update document including the upper fragment and an invalid element, wherein the invalid element specifies the version identifier of the earlier version of the lower fragment and indicates that information in the lower fragment is invalid. 19. The method of claim 14 , wherein the lower fragment is in XML format.