#Update-Package-Lists: 1 enable auto update, 0 for disable.
APT::Periodic::Update-Package-Lists "1";

#Download-Upgradeable-Packages: 1 enables auto download package, 0 for disable.
APT::Periodic::Download-Upgradeable-Packages "1";

#AutocleanInterval: Enable auto clean packages for X days. The configuration shows 3 days auto clean packages.
APT::Periodic::AutocleanInterval "3";

#Unattended-Upgrade: 1 enables auto upgrade, 0 for disable.
APT::Periodic::Unattended-Upgrade "1";