For the users of Debian Squeeze we, the KVIrc maintainers, plan to upload the soon-to-be-released upstream bug fix release 4.0.4, packages of RC2 are available. RC2 is most likely going to be identical to the final 4.0.4 release.
The update will be, if the SRMs agree (still need to ask them, but I wanted to wait for the final version before I do that), uploaded to stable-proposed-updates, maybe squeeze-updates and fix a few nasty bugs, which some users might experience, including graphical glitches when used under Gnome (upstream bug #1010), some crashes (e.g. upstream bugs #878, #879, #1093, #1098 and some without bug numbers like r4796), a regression in the Perl scripting support and a lot of translation updates (btw: if you use KVIrc and the translation for your mothertounge is lacking, consider to help! Coordinate your efforts on IRC.)
Apart from that I just uploaded a new SVN snapshot of 4.1 into Sid, the next will follow in about ten days unless you report bugs, which make an earlier upload necessary. ;-)