I found it on an ancient dovecot version, so it might be already fixed. Let's say I have a folder with 3 messages UID Subject Date 12 One 2013-06-09 11 Testmail 2013-06-10 14 Subject 2013-06-11 C: A0003 UID THREAD REFERENCES US-ASCII ALL S: * THREAD (12)(11)(14) Now I received a message with today's date (2013-06-12) with subject "Testmail" (the same as message with uid=11. The new message has uid=16. C: A0003 UID THREAD REFERENCES US-ASCII ALL S: * THREAD (12)((11)(16))(14) I expected 16 (or more likely 11 and 16) to be at the end of the result, after 14, i.e. (12)(14)((11)(16)). The problem for a user is when he has more messages in a folder. When user receives a new message sometimes (on subject duplicate) he will not see it because it will be somewhere in the middle of the result, but should be on top. -- Aleksander 'A.L.E.C' Machniak LAN Management System Developer [http://lms.org.pl] Roundcube Webmail Developer [http://roundcube.net] --------------------------------------------------- PGP: 19359DC1 @@ GG: 2275252 @@ WWW: http://alec.pl