Here, too, the upgrade now ran cleanly. Previously, there were problems with the Plasmaoid clock in the control bar. And also the desktop background "Wallpaper" did not work. Everything is OK again.
KDE Plasma Version: 5.26.90
KDE Frameworks Version: 5.102.0
Qt Version: 5.15.8
Kernel Version: 6.1.8-1-siduction-amd64 (64-bit)
Graphics Platform: X11
Graphics Processor: Mesa Intel® UHD Graphics 620