To update the Release Notes in the help handbook:

* For archival purposes, copy index.docbook to index-Rxx.yy.zz.docbook,
  where Rxx.yy.zz is the previous release version. For example.
  index-R14.0.0.docbook.

* Edit index.docbook as necessary for the next release. For example, R14.0.1.

No changes or updates are needed in ./release_notes.desktop or ../../release_notes.