A new feature of Ubuntu 18.04 LTS that wasn't in Ubuntu 16.04 LTS is that you can configure it to automatically install security updates. You can see that here on the installer screen:
I must confess, though, that I have mixed feelings about this. I mean, it's nice that the security updates get installed without me having to do anything, but a lot of those updates require that the system be rebooted before they can take effect. By default, Ubuntu systems don't automatically reboot after an update is installed. If you keep it that way, you'll see a message about it when you log in to the system. But if you ...
