I did not noticed the kernel version number but you're right. This is probably because my RAID set is degraded (it's a shame that Mac OS X doesn't nag the user until you open disk utility).
WoodyZ, I've been testing 10.8.4 beta without problems, I've not seen any major problem reports before installing, and for I prefer installing the latest OS on my development computer because I want to be in the same situation on most clients.
I know than most companies don't public release information about future release, but my question was more about a minor update fixing things with Mac OS X 10.8.4.