When updates are made to a document, they should be noted by (at least) a change element in the history. When more, or more localised, detail is desired, an update element can include notes within the text. There may be one or more update elements as the first children of those elements which include it as a child. The update element can also be placed immediately after a section title.
See the documentation of the history element for an example.
dl, figure, ol, p, px, span, subhead, table, ul
(px +
)
update |_(px+)
This links to the `versionid' attribute of one of the distribution or change elements in the history, and therefore implicitly provides the date and author of the change.