Apple release a OS X security update today, 2007-004. Apple doesn’t have a fixed schedule but they’ve released one security update a month so far this year. The patch contains 25 updates for 19 categories, see the screenshot for the list.
I installed it on my 24″ iMac without incident. The shutdown and reboot took longer than normal, long enough that I was beginning to get worried but it was fine. A second reboot took the usual amount of time.
I ran through my typical quick tests without a problem – start/stop iPhoto, Apple Mail, Thunderbird, iTunes (sync iPod), Chicken of the VNC, Firefox and Safari.
The Power PC (PPC) version of the update is 10.0 MB. Other than the download size, the software update information for the PPC version is the same as the Intel version. Installation on my PPC Mac Mini was also without incident.