http://www.rfc-editor.org/rfc/rfc7544.txt
RFC 7544: Mapping and Interworking of Diversion Information between Diversion and History-Info Header Fields in the Session Initiation Protocol (SIP), M. Mohali2015-08-01T23:00:00-00:00This document obsoletes RFC 6044, which describes the interworking between the Diversion header field defined in RFC 5806 and the obsoleted History-Info header field defined on RFC 4244.