The feature is problematic to implement. In an extreme case the last page may have no space to place a footer: it should force a page break and the trailing footer goes to new page with no content, which is undesired.
As a workaround it you may use a conditional page break to move some content to next page (if needed, to make the last page not totally blank) and a footnote.
Example:
[language=xml:ci6mh5m2]….
….
text text text …
the last text section…
….
….
trailing footer[/language:ci6mh5m2]
The page break will take effect only if the remaining vertical page space is less than 200px (and the last text section + footnote do not presumably fit it)
ifSpaceBelowLessThan parameter value for your document structure/layout needs to be found an empiric way.
