Hello,
we approach the time for a new stable version: http://www.kamailio.org/dokuwiki/doku.php/development:release-policy
Proposed date to freeze the code is: Mon, Jan 26, 2009. It will follow about one month of testing and the the new version will be out.
There is a lot of new development since last major release 1.4.0, check a summary at: http://www.kamailio.org/dokuwiki/doku.php/features:new-in-1.5.x
AFAIK, before release, 2-4 new more module are going to be introduced and couple of existing modules extended. This is a notification for all users and developers (existing or upcoming) to finish the work before the freezing data if they want to get their code in Kamailio (OpenSER) 1.5.0.
The 1.5.x series will be the last to use the current core. Next releases will be based on SIP Router project: http://sip-router.org/
Cheers, Daniel