Unattended upgrades does not remove old kernels that were installed by other means than unattended upgrades even if "Unattended-Upgrade::Remove-Unused-Dependencies "true";" is set in Trusty (and maybe in Precise) Bug #1492709
Unattended upgrades does not remove old kernels that were installed by other means than unattended upgrades even if "Unattended- Upgrade: :Remove- Unused- Dependencies "true";" is set in Trusty (and maybe in Precise) Bug #1492709