1. In a distributed system including an accessing message processor that is communicatively connectable to one or more other message processors such that the accessing message processor and the one or more other message processors can communicate by transferring electronic messages, a method for the accessing message processor to update session information for a communication session, the method comprising: accessing, by an application layer process running at an application layer of a communications protocol stack at the accessing message processor, a cached electronic message that includes an XML data structure contained within a SOAP envelope and that includes session information for establishing a communication session between the accessing message processor and at least one other message processor, the session information including at least one session element comprising at least one session identifier and at least one message sequence identifier, wherein the application layer comprises one of a plurality of distinct layers in the communications protocol stack that includes at least one lower protocol stack layer, and wherein the accessing message processor includes a session storage location that can be utilized to cache session information for communication sessions and includes a message storage location that can be used to cache received electronic messages; identifying, by the application layer process from within the cached electronic message, the session information of the communication session associated with the accessing message processor, and such that the application layer process identifies the session information, including said at least one session identifier and at least one message sequence identifier, as opposed to said session information being identified at the at least one lower protocol stack layer; determining that the accessing message processor is to update the session information cached at the accessing message processor such that the session information is updated by the application layer process of the accessing message processor rather than being updated at the at least one lower protocol stack layer of the accessing message processor, wherein said updating includes at least one of modifying, replacing, removing, or adding the session information; and routing the cached electronic message to another message processor included in the distributed system.