after d-u kontact/kmail comes up with
Cannot load library /usr/lib/x86_64-linux-gnu/qt5/plugins/kmailpart.so:
(libKF5MessageList.so.5abi1: Kann die Shared-Object-Datei nicht öffnen: Datei oder Verzeichnis nicht gefunden)
so kmail has been killed successfully.
Thanks for the warning.
This is also true for Akregator
$ akregator
akregator: error while loading shared libraries: libKF5MessageViewer.so.5abi1: cannot open shared object file: No such file or directory
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=986452
Seems to work fine with the libkf5messagelist5abi1 4:20.08.3-4 update.