root@mail:~# sudo vi /etc/apt/apt.conf.d/50unattended-upgrades
root@mail:~# sudo vi /etc/apt/apt.conf.d/20auto-upgrades
root@mail:~# cat /etc/apt/apt.conf.d/20auto-upgrades
APT::Periodic::Update-Package-Lists "1";
APT::Periodic::Unattended-Upgrade "1";
APT::Periodic::Download-Upgradeable-Packages "1";
//APT::Periodic::Verbose "1";
APT::Periodic::AutocleanInterval "7";

root@mail:~# sudo dpkg-reconfigure --priority=low unattended-upgrades
root@mail:~#