There should be button or promt for restart system after updates. Especially on KDE Linux where restart is important to apply latest updates. This needs to be done in Discover's systemd sysupdate backend. Alternative is to add Restart now or staging aka later on shutdown
There actually is a prompt, but it's not shown immediately after downloading the update due to a bug. If you restart the app and come back to the Updates page, you'll see it.
Git commit fac92468019ac719bbe8335d43eed42f503ca534 by Aleix Pol. Committed on 25/08/2025 at 01:31. Pushed by ngraham into branch 'master'. sysupdate: Fix ending of updates We'd update the version to "" (as indicated in the comment there). When successful, set the new installed version of the resource to the one that was available prior to the update. Otherwise it would end up in an odd state where it seems it hasn't updated but it actually has. M +2 -2 libdiscover/backends/SystemdSysupdateBackend/SystemdSysupdateResource.cpp https://invent.kde.org/plasma/discover/-/commit/fac92468019ac719bbe8335d43eed42f503ca534
*** Bug 506082 has been marked as a duplicate of this bug. ***