Yesterday I upgraded a machine from Debian “buster” to “bullseye” without apt-listchanges installed, oops. Here’s a way to get new NEWS.Debian entries after the fact.
perl -MDpkg::Changelog::Debian -wE'$parser = Dpkg::Changelog::Debian->new;
for (</usr/share/doc/*/NEWS.Debian*>) {
$parser->load($_);
$_->get_timepiece && $_->get_timepiece->year < 2020 ? last : say
for $parser->@* }' 2>&1 | mail -s"News for $(hostname)" you@example.com