Comment 51 for bug 1246364

Sometimes the update-notifier packages gets updated by Ubuntu. Then if you don't recompile / build new packages with the patches provided by Forest PPA, you may loose capabilities given by the patches.

You can simply block any update to the update-notifier packages by running these Terminal cmd. lines:

$ sudo echo "update-notifier hold" | dpkg --set-selections
$ sudo echo "update-notifier-common hold" | dpkg --set-selections

To revert the changes:

$ sudo echo "update-notifier install" | dpkg --set-selections
$ sudo echo "update-notifier-common install" | dpkg --set-selections

You can as well set it in a Bash script block-upd-update-notifier:

#!/bin/sh
#
if [ $(id -u) != 0 ]; then
   echo "This script requires root permissions"
   sudo "$0"
   exit
fi
echo "update-notifier hold" | dpkg --set-selections
echo "update-notifier-common hold" | dpkg --set-selections

The same goes for unblock-upd-update-notifier

I guess the change was an Ubuntu policy change about the updates as they like to force them a bit like Microsoft does. I don't expect them to ever revert to the previous behaviour.