I upgraded to Fedora 24 (from Fedora 23) and had two problems:
The upgrade apparently deleted kdm and did not enable sddm as my login
manager, so no graphical login. A "sudo systemctl --force enable
sddm.service" corrected the problem. Oh well, I guess I should not
have continued with kdm so long. :-)
Kmail ignored my settings[*] and created settings as if I never had
any. It _did_ know where my mail was. I had to copy kmail2rc from
~/.kde/share/config to ~/.config .
All is well now.
[*] This is quite irritating since the KDE developers have been doing
this sort of thing with the entire suite over the last several years.
They have shown a complete disdain for users' settings for all of the
KDE desktop applications and environment. It is amazing to me that it
still goes on.
Garry T. Williams