Comment 13 for bug 1223321

Another consequence of update-notifier not being aware of phased updates is that update-manager may auto-launch telling you your system is up to date.

This happens because update-notifier uses /usr/lib/update-notifier/apt-check to see whether or not there are updates available to install. However, apt-check does not take into consideration whether or not an update is phased. Then if update-notifier determines that updates are available and update-notifier's auto-launch (of update-manager) is set to true (the default), then update-manager will launch and inform you that your system is up to date.