@item -d, --diff-version-update
increase the @code{\version} string only if the file has actually
been changed. In that case, the version header will correspond to
-the version after the last actual change. Without that option,
-the version will reflect the last @emph{attempted} conversion.
+the version after the last actual change. An unstable version
+number will be rounded up to the next stable version number unless
+that would exceed the target version number. Without this option,
+the version will instead reflect the last @emph{attempted}
+conversion.
@item -e, --edit
Apply the conversions direct to the input file, modifying it