After waiting through the install phase and requisite reboot, my machine came up in 10.5.7, ready for use. On the surface, there's nothing visually different about this update. Apple notes only a few changes that may be noticeable at a glance--more RAW image support, better video playback and cursor movement on recent Nvidia-powered Macs, and the ability to grant non-admin users to add and remove printers via the Parental Controls System Preferences panel.
Most of the changes here are below the surface, and as you'd expect with a nearly half-gigabyte update, widespread. To see what Apple has modified, I dug into the update's BOM file (for more on BOM files; see this ; in 10.5.x, you'll find the BOM files in the /Library -> Receipts -> boms folder).
The list of programs touched by this updater is large, though not all get new version numbers (indicating the changes are very minor). Here's what's been updated, based on the BOM file, and the new version number if applicable; if not shown, it's unchanged from 10.5.6: Address Book (4.1.2), Automator (2.0.3), Dashboard, DVD Player, Exposé, Front Row, iCal (3.0.7), iChat (4.0.8), Mail (3.6), Preview (4.2), Safari 4 Beta, Spaces, Time Machine, Bluetooth File Exchange (2.1.6), RAID Utility (1.0.3), Remote Install Mac OS X, System Profiler (10.5.7; this is updated each cycle), Terminal (2.0.2), and X11. Whew, that's quite a list!
Note that if you have Safari 4 Beta installed, after upgrading to 10.5.7, you should run Software Update again. When you do, you'll see a separate 31.8MB Safari 4 Beta update. Run this updater (which will require another restart) to patch Safari 4 Beta against these known . After running this update, the build number of Safari 4 Beta (visible in the Safari -> About Safari dialog) will be 5528.17.
What's most surprising about the number of modified applications is that very few of those are mentioned on --only Dashboard, Time Machine, iCal and Mail are directly called out, but none of the rest. Although the BOM file makes it simple to see exactly which files were modified within an application, this doesn't necessarily help figure out exactly what the purpose of the change was.
For example, the BOM file indicates that changes were made to iChat's balloons, boxes, compact, and text view styles. But comparing those views on my 10.5.6 and 10.5.7 machines reveals no visible differences. I could, of course, use a program like diff (or FileMerge, part of Xcode) to compare the files--text files, at any rate--to see where the differences lie. But with 449MB worth of data, that would be a horrendously time-consuming project.
Instead, I launched each of the modified programs, looking for any visible differences in menus or preferences, as compared to the 10.5.6 version of the same program (running on a not-yet-updated machine). However, nothing obvious jumped out at me in the way of new features in any of these programs. Then again, I've only been able to spend a few minutes comparing each program, so perhaps I've overlooked something--if you spot any new features, feel free to post them in the comments.
In System Preferences, there are changes to the following panels: Bluetooth, Desktop & Screen Saver, Energy Saver, MobileMe, Parental Controls, Print & Fax, Sound, Startup Disk, Time Machine, Trackpad, and Universal Access. As with the applications, however, I couldn't spot any visible differences when comparing the same panes on 10.5.6 and 10.5.7 machines.
Beyond the changes to applications and System Preferences, there are changes in low-lying technologies, too. The BOM file reveals changes to the iLife Media Browser; EPSON scanner drivers; Flash and Shockwave players; Quick Look generators for iWork; 802.11 and RAID frameworks; Spotlight importers for Office, iWork and (somewhat of a surprise) AppleWorks; updates to many Automator actions; a slew of changes to Bluetooth, including changes to the Bluetooth Setup Assistant; and lots of changes to audio and video (both ATI and Nvidia) drivers.
Finally, there were a ton of updates on the Unix side of OS X. Most notably, Apache 2 (2.2.11) and PHP (5.2.8) were both updated, as were some Perl libraries, various Python and Ruby frameworks, and a whole bunch of Unix utilities. There are also updates to many of the X11 Unix programs.
I've been tracking OS X updates for quite a while, and this one ranks among the largest ever. Dumping the BOM file into a text file, and then opening it in BBEdit reveals a total of 16,915 changed files on my MacBook Pro. Despite that, things seem to be running very smoothly here after the update. I've been using the machine for a few hours now, and haven't noticed any problems--I wasn't having any before with this machine, so it's a good thing when an update doesn't have negative consequences. As always, though, your mileage may vary, so please, back up your key files before updating.