Version:           1.12.1 (using 4.3.1 (KDE 4.3.1), Debian packages)
Compiler:          cc
OS:                Linux (i686) release 2.6.31-1.slh.7-sidux-686

Alas the buttons for jumping to the next/previous unread message in a folder (and the keys +/-) don't cycle through the messages in this folder when reaching the end of the list. It would be very helpful when the Next button would jump to the beginning of the folder when there are unread messages before the current one so I can browse through the rest of the unread mails forward. 

In my case kmail jumps to the last read message when I look into a folder. There can be new messages before and after that message. When I'm at the end of the list and there are no further unread mails but one I can jump to it with the Previous button (or minus). But when there are several unread messages above the point from which I started I only can go through the mails backwards when I use the Previous button until I reach the top. But what I want and had expected is to go forward from the beginning of the list, always same direction in a cycle.

I never used the Next/Previous feature before but now with the new group sorting it seems like a good idea to me and I was very puzzled that the keys don't cycle at the end of the list.