The package is severely out of date with respect to the Debian
Policy. Latest version is 4.5.1
and your package only follows
3.9.6...
The package has a debian/watch file, but the last attempt
to use it for checking for newer upstream versions failed with
an error:
In debian/watch no matching files for watch line https://download.gnome.org/sources/nemiver/([\d\.]+)/ nemiver(?:[-_]?(\d[\-+\.:\~\da-zA-Z]*))\.tar\.xz