Comment 65 for bug 1560797

If /usr/lib/ubuntu-release-upgrader/check-new-release-gtk is used, which is called by the update-notifier release upgrade notification, the upgrade can start without first upgrading the system (because update-manager is by passed). It is possible to make ubuntu-release-upgrader require certain packages be installed before starting the release upgrade and it seems like we should require the new version of apt.