// Enable the update/upgrade script (0=disable)
APT::Periodic::Enable "1";
 
// Do "apt-get update" automatically every n-days (0=disable)
APT::Periodic::Update-Package-Lists "1";
 
// Do "apt-get upgrade --download-only" every n-days (0=disable)
APT::Periodic::Download-Upgradeable-Packages "1";
 
// Run the "unattended-upgrade" security upgrade script
// every n-days (0=disabled)
// Requires the package "unattended-upgrades" and will write
// a log in /var/log/unattended-upgrades
APT::Periodic::Unattended-Upgrade "1";
 
// Do "apt-get autoclean" every n-days (0=disable)
APT::Periodic::AutocleanInterval "7";