Observe #1267059 about 'Unattended-Upgrade::Remove-Unused-Dependencies' not working as expected for old versions of unattended-upgrades, also resulting e.g. in obsolete kernel packages not getting removed.
Observe #1267059 about 'Unattended- Upgrade: :Remove- Unused- Dependencies' not working as expected for old versions of unattended- upgrades, also resulting e.g. in obsolete kernel packages not getting removed.