ok, so KDE 4.7 is out.
Ye-haw.
After updating to 4.7, kmail complains on startup (which takes ages, btw) that “the server does not support TLS”. It sure would help to know which server. It also would help to be able to get at my mails at all; all my folders are completely empty. Oh, and deleting a mail from one of the folders that are not empty doesn’t work either.
rollback time.
Most likely you should dig into akonadi (just type it into the menu search box).
Most likely the KDE folks shouldn’t post stuff like “Version 4.7 of these releases provide many new features and improved stability and performance.” (Quote from the announcement for 4.7), when on the other hand some mailing lists talk like this:
“kmail2, after some extensive tunig and fiddling and manual intervention, is almost as fast as the old version, it just uses way more ram.”