This document defines extensions to core features of the Extensible Messaging and Presence Protocol (XMPP) that provide basic instant messaging (IM) and presence functionality in conformance with the requirements in RFC 2779. This document obsoletes RFC 3921.
RFC 6121-2011 history
2011RFC 6121-2011 Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence