currently, KDE-unstable only contains the Framework (Kde Framework 6) - the actual desktop is still missing - we have to see what Group name it will get. You will have to install those packages, too.
sudo pacman -Syu should be enough once the pacakges have been installed.
The packages in KDE-unstable currently are no upgrade to any packages in the stable repo’s - thats the basic thing about my statement in the post above. But if those packages get updates, the usual update mechanism works.
Not sure how you set up your /home partition, but I recommend you create a new and distinct user for Plasma 6, too.
I’m planning to do the Plasma 6 testing on a separate install on its own partition (say sda5). So, there will be just one user.
Or do you think that if I use the same user name as on my normal install (on ada1) that might still be a risk?
I would recommend a test installation in a virtual machine
I do have experience with VM’s - so that’s certainly an option. Thanks.
In the end, you’re not doing anything wrong with a virtual machine. You can shoot everything down without consequences 
I have installed qemu. I use it to test all kinds of things.
https://discovery.endeavouros.com/applications/how-to-install-virt-manager-complete-edition/2021/09/
the actual Plasma 6 Desktop just landed in KDE-unstable and THOSE packages ARE direct upgrades to existing packages and they pull in the correct Framework packages as dependencies. So it should be as easy as adding the KDE-unstable repository and updating. The new user should definitely be used so that no old configs are the reason for bugs.
Thanks for the heads-up - will prepare the setup and start testing.
You probably want to wait until the KDE Gear - all the KDE applications - drops too.
Indeed. Good idea. Thanks.
Where will Gear drop? Here?:
So… I had some spare time and, well, against all your good advice went and did and done it 
.
I was too curious to wait any longer…
Wiped sda5 (bye bye Manjaro 
), installed the latest ISO, updated with refreshed mirrors, updated the system (all with Welcome-app), rebooted, added kde-unstable and updated again, and…
NOTHING. 
That is to say: just a bunch of messages that the local packages were newer than the remote packages.
I changed the order of the mirrors in /etc/pacman.d/mirrorlist.
Redid the update and lots of updates were installed. 
Rebooted.
At the login screen it was already clear that I should have listened to you and waited a bit longer.
Several messages of missing files in a very Windows3.11-like login-screen.
I could login though.
Desktop didn’t show up. An error message that the folder view could not be shown and a window (that couldn’t be closed) with:
file:///usr/lib/qt6/qml/org/kde/plasma/private/containmentlayoutmanager/BasicAppletContainer.qml:131:9: Type DropShadow unavailable
qrc:/qt-project.org/imports/Qt5Compat/GraphicalEffects/DropShadow.qml:6:1: Kan bibliotheek /usr/lib/qt6/qml/Qt5Compat/GraphicalEffects/private/libqtgraphicaleffectsprivateplugin.so niet laden: (libQt6ShaderTools.so.6: kan gedeeld objectbestand niet openen: Bestand of map bestaat niet)
More missing files.
The starter menu did not work either.
The taskbar and panel were very much off-kilter.
To shut down I had to open a terminal (CTRL-K did work ) and use the command line.
In short: my advice to you all is to follow your own advice and wait a bit longer.
I did it, so you need not do it just yet.
I’m glad you did, I might have
I did a peek today too. Logging-in was a problem. The desktop is missing the the qt6-shadertools package at the moment - after installing that it showed up fine here.
But I rolled back too. If you aren’t a developer it’s probably best to wait two weeks for the first beta. That gives the arch-packager time to figure things out. And there seems to be enough things to work on that the KDE people are busy anyway.
Sound advice.
Progress today!
After logging in today I ran yay in terminal. Packages were upgraded and added, amongst which qt6-shadertools. After reboot I had a normal login screen, and after logging in I had a normal desktop.
Behold.
Lots of things still do not work, though.
But KDE-devs are clearly working hard at getting Plasma 6 Beta up and running.
After configuring the “Plasma 6 EOS” a tiny bit I am happy to be able to say that I’m typing this from that setup. Will tinker a bit more tonight…
I’ve now been using my “Plasma 6” (pre beta) for two days.
My preferred office suite, mail client and terminal run without problems so far.
I’ll add some more applications coming week.
At first I couldn´t set up the right keyboard layout, but yesterday that worked as well.
Only thing that I noticed doesn’t work is the Meta-1, Meta-2 etc keys to start the apps that are pinned to the panel.
KDE devs seem to be adding updates and packages to kde-unstable at least a once a day.
Edit:
Some more info about Plasma 6/Qt6, including links to known issues:
Changing the panel is different in Plasma 6.
Entering the change mode:
Choosing to change the position of the panel:
Trying to get my panel to the left has failed so far: Plasma crashes every time I try (also whilst making these screenshots).
In short: Plasma 6 is not quite finished yet. 
Edit: just ran yay, some items from kde-unstable were updated and now I’ve been able to move the panel to the left. Not sure if there is a connection, though.
Next step: find out which logs are needed to be able to see the Plasma 6/QT 6 error messages that do occur, to then be able to report them at https://bugs.kde.org/.
Thanks - I’ll have a read.
At the moment the startmenu (kickoff?) is not working. In stead of the menu a message appears:
file:///usr/share/plasma/plasmoids/org.kde.plasma.kickoff/contents/ui/main.qml:20:1: Kan bibliotheek /usr/lib/qt6/qml/org/kde/plasma/private/kicker/libkickerplugin.so niet laden: (libAppStreamQt.so.3: kan gedeeld objectbestand niet openen: Bestand of map bestaat niet)
Can’t load library, can’t open shared object file: file or folder does not exist…
I’ll have a look at bugs.kde.org to see if that has been reported already.
