Comment # 14 on bug 1004343 from Jonathan Kang

(In reply to Dominique Leuenberger from comment #13)
> (In reply to Felix Zhang from comment #12)
> 
> > I would. But Jonathan was fast and has pushed a request already. :-)
> 
> Yes, Jonathan was faster :)
> 
> but there is an issue as Bjorn reported in comment #9: it pops up a dialog
> claiming 'updates are installed' instead of 'updates are available'

That's the result of a successful PK offline update. The result is stored in
/var/lib/PackageKit/offline-update-competed.

The dconf keys in "org.gnome.settings-daemon.plugins.updates" defines how often
the updates plugin checks update and bring the notification.