&xep0012; defines a method for determining the last time that an XMPP entity was active. This document specifies that an online client MAY include last activity information when sending presence updates. The prototypical use case is including the idle time when automatically setting the user's &SHOW; value to "away" or "xa" (extended away). For example, consider a user who has configured her client to automatically change her presence to "away" after 10 minutes of inactivity. The client could include an iq:last flag to specify how long the user has been idle.

If one of the user's contacts receives that presence notification with delayed delivery (see &xep0203;) on login in response to a presence probe as described in &xmppim;, the contact will then know how long the user has been idle (i.e., the number of seconds since the delayed delivery timestamp, plus the iq:last seconds). Thus the contact does not need to send an iq:last query.

Including a last activity notation in presence notifications can enable those who receive such notifications to determine exactly when a user has stopped interacting with his or her XMPP client, but this information is in essence already available if the user publishes timely presence updates. Therefore, this specification introduces no new vulnerabilities.

This document requires no interaction with &IANA;.

This document requires no interaction with the ®ISTRAR;.