/etc/apt/apt.conf.d/20auto-upgrades:

	APT::Periodic::Update-Package-Lists "1";
	APT::Periodic::Download-Upgradeable-Packages "1";
	APT::Periodic::AutocleanInterval "7";
	APT::Periodic::Unattended-Upgrade "1";



/etc/apt/apt.conf.d/50unattended-upgrades:

	Unattended-Upgrade::Allowed-Origins {
			"${distro_id}:${distro_codename}";
			"${distro_id}:${distro_codename}-security";
			// Extended Security Maintenance; doesn't necessarily exist for
			// every release and this system may not have it installed, but if
			// available, the policy for updates is such that unattended-upgrades
			// should also install from here by default.
			"${distro_id}ESM:${distro_codename}";
			"${distro_id}:${distro_codename}-updates";
	//      "${distro_id}:${distro_codename}-proposed";
	//      "${distro_id}:${distro_codename}-backports";
	};

	// List of packages to not update (regexp are supported)
	Unattended-Upgrade::Package-Blacklist {
	//      "vim";
	//      "libc6";
	//      "libc6-dev";
	//      "libc6-i686";
	};

	// This option allows you to control if on a unclean dpkg exit
	// unattended-upgrades will automatically run
	//   dpkg --force-confold --configure -a
	// The default is true, to ensure updates keep getting installed
	//Unattended-Upgrade::AutoFixInterruptedDpkg "false";

	// Split the upgrade into the smallest possible chunks so that
	// they can be interrupted with SIGUSR1. This makes the upgrade
	// a bit slower but it has the benefit that shutdown while a upgrade
	// is running is possible (with a small delay)
	//Unattended-Upgrade::MinimalSteps "true";

	// Install all unattended-upgrades when the machine is shuting down
	// instead of doing it in the background while the machine is running
	// This will (obviously) make shutdown slower
	//Unattended-Upgrade::InstallOnShutdown "true";

	// Send email to this address for problems or packages upgrades
	// If empty or unset then no email is sent, make sure that you
	// have a working mail setup on your system. A package that provides
	// 'mailx' must be installed. E.g. "[email protected]"
	//Unattended-Upgrade::Mail "root";

	// Set this value to "true" to get emails only on errors. Default
	// is to always send a mail if Unattended-Upgrade::Mail is set
	//Unattended-Upgrade::MailOnlyOnError "true";

	// Do automatic removal of new unused dependencies after the upgrade
	// (equivalent to apt-get autoremove)
	//Unattended-Upgrade::Remove-Unused-Dependencies "false";

	// Automatically reboot *WITHOUT CONFIRMATION*
	//  if the file /var/run/reboot-required is found after the upgrade
	//Unattended-Upgrade::Automatic-Reboot "false";

	// If automatic reboot is enabled and needed, reboot at the specific
	// time instead of immediately
	//  Default: "now"
	//Unattended-Upgrade::Automatic-Reboot-Time "02:00";

	// Use apt bandwidth limit feature, this example limits the download
	// speed to 70kb/sec
	//Acquire::http::Dl-Limit "70";


/var/log/unattended-upgrades/unattended-upgrades.log

	2017-09-19 06:27:45,087 INFO Initial blacklisted packages:
	2017-09-19 06:27:45,088 INFO Initial whitelisted packages:
	2017-09-19 06:27:45,088 INFO Starting unattended upgrades script
	2017-09-19 06:27:45,088 INFO Allowed origins are: ['o=Ubuntu,a=xenial', 'o=Ubuntu,a=xenial-security', 'o=UbuntuESM,a=xenial', 'o=Ubuntu,a=xenial-updates']
	2017-09-19 06:27:49,681 INFO No packages found that can be upgraded unattended and no pending auto-removals

	
# apt-get upgrade

	Reading package lists... Done
	Building dependency tree
	Reading state information... Done
	Calculating upgrade... Done
	The following packages were automatically installed and are no longer required:
	  linux-headers-4.4.0-79 linux-headers-4.4.0-79-generic linux-headers-4.4.0-92 linux-headers-4.4.0-92-generic linux-image-4.4.0-79-generic linux-image-4.4.0-92-generic linux-image-extra-4.4.0-79-generic linux-image-extra-4.4.0-92-generic
	Use 'apt autoremove' to remove them.
	The following packages will be upgraded:
	  libxml2
	1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.