Version: (using KDE 4.4.2) OS: Linux Installed from: Ubuntu Packages My mail folders have been around for a long time, so many of them are still in mailbox or mbox format. Kudos to kmail for supporting them without trouble. I've recently noticed that having large, frequently changing, mbox files is causing real problems with both nepomuk indexing and rsync backups. Switching to maildir is essential for me to have a workable desktop system. I would love it if kmail allowed me to right-click a folder and select "Convert to maildir format" and it took care of it for me. I've not found a good tool to do this with, so I've been working by hand. Mostly, I've been using kmail to do it. I create a new folder which is maildir by default, then move all the messages from the old folder to the new one. Then I delete the old folder and rename the new one. For converting my inbox, sent mail, and trash folders, after moving the messages I stop kmail and remove the inbox, sent mail, and trash. On restart they are recreated. Then I move the messages back. So you see, kmail already has most of the required capability, it just needs to be organized correctly.
Thank you for your feature request. Kmail1 is currently unmaintained so we are closing all wishes. Please feel free to reopen a feature request for Kmail2 if it has not already been implemented. Thank you for your understanding.
Instead of creating a new feature request, please confirm here if the wishlist is still valid for kmail2.