The updates applet is not available in the system tray in 5.8.0. After removing the "X-KDE-ParentApp" line from metadata.desktop it shows up again. Reproducible: Always
Git commit c5de9b8b7c58f3e616c3798f31288107600aa708 by Aleix Pol. Committed on 03/10/2016 at 10:59. Pushed by apol into branch 'Plasma/5.8'. Let the parentapp be the default one M +0 -1 notifier/plasmoid/metadata.desktop http://commits.kde.org/discover/c5de9b8b7c58f3e616c3798f31288107600aa708
*** Bug 370262 has been marked as a duplicate of this bug. ***