In Ubuntu 16.04 xenial I've installed unattended-upgrades about six months ago.
sudo apt-get install unattended-upgrades
sudo dpkg-reconfigure --priority=low unattended-upgrades
after that time I ran in console:
apt-get update -y && apt-get upgrade -y
About 45 packages were totally upgraded.
I thought I should see about 5-10, but not about 45… This amout of upgrades surprised me a bit, as if, seemingly, unattended-upgrades "didn't do all the job".
Why unattended-upgrades upgraded so few packages, seemingly?
Best Answer
Most of the answer is in your unattended-upgrades logfile, located at
/var/log/unattended-upgrades/unattended-upgrades.log
Here's an example:
Take a look at that middle line 'Allowed origins'. That means Software Repositories. The only source there is -security. Not -upgrades, not -backports, no PPAs, no third-party repos.
In other words, this example unattended-upgrades is only providing security upgrades. Nothing else.
You can add, remove, or edit Allowed Origins (repositories) through the Software and Updates Control Panel, or by editing the unattended-upgrades config file, located at
/etc/apt/apt.conf.d/50unattended-upgrades
.The rest of the answer is that Xenial (16.04) is two years old. Fewer new security updates for old software.