 This document introduces a new MIME-Type "application/pidf-diff+xml" that enables transporting of either only the changed parts or the full PIDF- based presence information. The root element of the document distinguishes whether the partial or full PIDF document content was transported. (5) Timed Presence [16]: Traditionally, presence information, e.g., represen- ted as PIDF and RPID, describes the current state of the presentity. However, a watcher can better plan communications if it knows about the presentity's future plans. For example, if a watcher knows that the presentity is about to travel, it might place a phone call earlier. It is also occasionally useful to represent past information since it may be the only known presence infor- mation; it may give watchers an indication of the current status. For exam- ple, indicating that the presentity was at an off-site meeting that ended an C 2009 by Taylor & Francis Group, LLC SIP Event Notification and Presence Information hour ago indicates that the presentity is likely in transit at the current time. This document defines the <timed-status> element that describes the sta- tus of a presentity that is either no longer valid or covers some future time period. (6) Location data [17]: While not specifically part of the SIMPLE work, a related working group called GEOPRIV has developed an extension to PIDF for transporting location data. Location data is likely to become more impor- tant and pervasive in the future and it makes sense to define a way of its expression since it is closely related to the properties defined above. Also, location data can facilitate location-based services, can be gathered automat- ically with no effort from the user, and is a valuable bit of information in determining the situation the user is in. References [1] Rosenberg, J., H. Schulzrinne, G. Camarillo, A.R. Johnston, J. Peterson, R. Sparks, M. Handley, and E. Schooler. 2002. SIP: session initiation protocol. In RFC 3261, Internet Engineering Task Force, June. [2] Roach, A.B. 2002. 