Comment 2 for bug 1348227

I saw this with an install based on 12.04.3 media. Today I did a full-upgrade and this is what I got as motd and with running "hwe-support-status --verbose':

===
Your current Hardware Enablement Stack (HWE) is going out of support
on 08/07/14. After this date security updates for critical parts (kernel
and graphics stack) of your system will no longer be available.

For more information, please see:
http://wiki.ubuntu.com/1204_HWE_EOL

To upgrade to a supported (or longer supported) configuration:

* Upgrade from Ubuntu 12.04 LTS to Ubuntu 14.04 LTS by running:
sudo do-release-upgrade

OR

* Install a newer HWE version by running:
sudo apt-get install linux-generic-lts-trusty libgl1-mesa-glx-lts-trusty xserver-xorg-lts-trusty linux-image-generic-lts-trusty

and reboot your system.
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I confirmed that update-manager is installed:

$ dpkg-query -W update-manager
update-manager 1:0.156.14.15