This protocol describes a way to communicate a user's last interaction time with other XMPP entities over &PRESENCE; stanzas. For the purposes of this document, user interaction here refers to a human end user interacting with her device by means of a keyboard, mouse, touch screen, and so on. Based on this information XMPP clients can display the time a contact went idle or a duration for how long a contact has been idle, thereby allowing end users to estimate the expected responsiveness of their contacts.

This protocol uses absolute timestamps formatted according to &xep0082;, indicated as value of the 'since' attribute in the <idle/> element.

Experience has shown a number of issues with &xep0256;:

• The use of relative durations is too vague. It requires additional information from &xep0203; to provide a reliable user experience.
• Distinguishing between the idle and last online use cases is very difficult.
• It is desirable to have idle time indiciated for &PRESENCE; <show/> values other than "away" and "xa".

Updating XEP-0256 directly would be problematic as it would break compatibility with existing implementations. Instead a new protocol is described for handling the idle time use case; the last online use case is handled by &xep0312;.

There are two main use cases for this extension, explained in more detail in the following sections.

Thanks to Florian Schmaus, Christian Schudt, and Lance Stout for their helpful comments.

The security considerations of XEP-0082 apply to this protocol.

This specification introduces no new security or privacy concerns. While including a last user interaction notation in &PRESENCE; updates can enable recipients to determine exactly when a user has stopped interacting with her XMPP client or even their system, this information is in essence already available if the user's client publishes timely presence updates.

This document requires no interaction with &IANA;.