####apt::unattended_upgrades
+* `legacy_origin`: If set to true, use the old `Unattended-Upgrade::Allowed-Origins` variable. If false, use `Unattended-Upgrade::Origins-Pattern`. OS-dependent defaults are defined in `apt::params`.
* `origins`: The repositories from which to automatically upgrade included packages.
* `blacklist`: A list of packages to **not** automatically upgrade.
* `update`: How often, in days, to run `apt-get update`.