If the update type is relogin suggested or reboot suggested, it should be possible for Apper to tell the session to reboot or logout. Not sure of the api to do this but there should be something desktop neutral available via kwindowsystem?
Apper already has the functionality to tell the user he needs to restart or relogin. But it's the backend task to infor it. If zypper pm support this then the zypp backaend needs to be updated. (guessing you are running suse)
Created attachment 64913 [details] missing reboot icon in notifier?
Thanks I see that now, in TransactionWatcher::logout(). I once saw the relogin icon in the panel but did not recognise it, and now the notifier is just blank and has an empty context menu, see attachment. I checked the api and you should use the function KWorkSpace::requestShutDown() to perform the logout/reboot instead of hitting KSMServer directly: http://api.kde.org/4.x-api/kde-workspace-apidocs/libs/kworkspace/html/namespaceKWorkSpace.html#a0d3e4e1632c4d0e57778faabf713b1d7
*** Bug 287318 has been marked as a duplicate of this bug. ***
Fix for the empty icon on the systray and make use of KWorkSpace::requestShutdown as Will Stephenson pointed out: http://commits.kde.org/apper/c00e591a0a15906da4610b6d2750f80a32da5fd7