Version:           4.7 (using KDE 4.7.3) 
OS:                Linux

My imap server is able to handle the IDLE command (thunderbird works with this), but kmail2 does not use it.

I have to enable cyclic polling to get new mails shown.

Reproducible: Always

Steps to Reproduce:
disable cyclic polling and send in new mail.

Actual Results:  
No new mail is shown in kmail. Only if F5 of ctrl-L is pressed new mails are listed.

Expected Results:  
list new mails

My imap server is cyrus version 2.3.7. On request from Andras Mantia I enabled imap logging and the first lines are:

C: A000004 CAPABILITY
S: * CAPABILITY IMAP4 IMAP4rev1 LITERAL+ ID LOGINDISABLED ACL
RIGHTS=kxte QUOTA MAILBOX-REFERRALS NAMESPACE UIDPLUS NO_ATOMIC_RENAME
UNSELECT CHILDREN MULTIAPPEND BINARY SORT SORT=MODSEQ
THREAD=ORDEREDSUBJECT THREAD=REFERENCES ANNOTATEMORE CATENATE CONDSTORE
IDLE LISTEXT LIST-SUBSCRIBED X-NETSCAPE URLAUTH
S: A000004 OK Completed
C: A000005 NAMESPACE
S: * NAMESPACE ( ("INBOX." ".") ) ( ("user." ".") ) ( ("" ".") )
S: A000005 OK Completed
C: A000006 LIST "" *

Then there is a long list of Folders with hasChildren or hasNoChildren
and after that

S: A000006 OK Completed ( 0.010 secs 165 calls )
C: A000007 LSUB "" *

and a long list of LSUB entries of the folders. After this I selected my
SOGo folder and got:

S: A000007 OK Completed ( 0.000 secs 103 calls )
C: A000008 SELECT "INBOX.Listen.SOGo"
S: * FLAGS ( \Answered \Flagged \Draft \Deleted \Seen KMAILFORWARDED
KMAILTODO KMAILWATCHED KMAILIGNORED $FORWARDED $TODO $WATCHED $IGNORED
$SIGNED $ATTACHMENT $REPLIED )
S: * OK [ PERMANENTFLAGS ( \Answered \Flagged \Draft \Deleted \Seen
KMAILFORWARDED KMAILTODO KMAILWATCHED KMAILIGNORED $FORWARDED $TODO
$WATCHED $IGNORED $SIGNED $ATTACHMENT $REPLIED \* )  ]
S: * 1473 EXISTS
S: * 0 RECENT
S: * OK [ UNSEEN 1472  ]
S: * OK [ UIDVALIDITY 1279521570  ]
S: * OK [ UIDNEXT 7327  ]
S: * OK Sorry, modsequences have not been enabled on this mailbox [
NOMODSEQ  ]
S: A000008 OK Completed [ READ-WRITE  ]
C: A000009 EXPUNGE
S: * 1473 EXISTS
S: * 0 RECENT
S: A000009 OK Completed
C: A000010 SELECT "INBOX.Listen.SOGo"
S: * FLAGS ( \Answered \Flagged \Draft \Deleted \Seen KMAILFORWARDED
KMAILTODO KMAILWATCHED KMAILIGNORED $FORWARDED $TODO $WATCHED $IGNORED
$SIGNED $ATTACHMENT $REPLIED )
S: * OK [ PERMANENTFLAGS ( \Answered \Flagged \Draft \Deleted \Seen
KMAILFORWARDED KMAILTODO KMAILWATCHED KMAILIGNORED $FORWARDED $TODO
$WATCHED $IGNORED $SIGNED $ATTACHMENT $REPLIED \* )  ]
S: * 1473 EXISTS
S: * 0 RECENT
S: * OK [ UNSEEN 1472  ]
S: * OK [ UIDVALIDITY 1279521570  ]
S: * OK [ UIDNEXT 7327  ]
S: * OK Sorry, modsequences have not been enabled on this mailbox [
NOMODSEQ  ]
S: A000010 OK Completed [ READ-WRITE  ]

with a long list of numbers (IDs of the mails) and the last mail selected.

And Andras wrote that there shoulb be something like

C: A000006 IDLE
S: + idling

but is not.