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Last Presence using Delayed Delivery This specification defines a way to determine the time when a XMPP entity has last changed its presence. &LEGALNOTICE; 0318 Experimental Informational Standards XMPP Core XMPP IM XEP-0203 XEP-0012 last-presence &tobias; 0.1 2013-03-04 psa

Initial published version approved by the XMPP Council.

 0.0.1 2013-02-20 tobias

Initial version.

This protocol describes a way to communicate time of last presence change with other XMPP entities over presence stanzas. This is done extending presence stanzas with delayed delivery information according to &xep0203; and can be used to determine the time of last presence change for XMPP entities includeing servers. For users on the same server, the server also adds delyed delivery information to the presence responses.

The time of the delayed delivery information attatched to the presence indicates the time a XMPP entity has last changed to this presence.

This section describes how to determine the time a user when offline or, in general, changed to her current presence state. This is merly a description since the protocol is already described in &rfc6121;, section 4.3.2.

The following example show a possible incoming presence in response to going online by sending your own available presence.

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Reqesting the uptime of a server or component is done by sending a directed presence probe to the XMPP entity of interest. The request is shown in the following example.

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The server or component then responds with an available presence, extended with delayed delivery information, according to &xep0203;, indicating its startup time. This is shown below:

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Thanks to Kim Alvefur and Lance Stout for their helpful comments.

Adding delayed delivery notation to the presence probe responses exposes information a user might not expect to have exposed. However the information about last presence change is known to all entities subscribed to one's presence which are online. This extension just provides this information to XMPP entities which have been offline during the course of presence change.

It's worth to note that the security considerations of &xep0082; apply here.

This document requires no interaction with &IANA;.

This document requires no interaction with the ®ISTRAR;.