Apple has released the anticipated OS X 10.6.7 update, after weeks of developer build seeds that were issued with no new features or fixes. The update is available in the normal versions of delta and combo updaters for both the client and server versions of OS X, and should be available via Software Update for most people. This update is especially important for owners of the new 2011 MacBook Pro systems because it addresses a graphics bug that caused hangs and crashes under heavy graphics load.
You can download the standalone updaters from the following links:
Mac OS X v10.6.7 Update (475MB)
Mac OS X v10.6.7 Update Combo (1.12GB)
Mac OS X Server v10.6.7 Update (541.21MB)
Mac OS X Server v10.6.7 Update Combo (1.15GB)
Apple has released a separate update for the latest MacBook Pro systems. As we noted earlier, these systems shipped with a graphics bug that caused hangs and crashes, and this update specifically notes that it "improves graphics stability and external display compatibility" in these new systems. Be sure that if you choose to manually install the update for your system that you choose this one if your MacBook Pro is a newly purchased one.
In general, the OS update addresses reliability of Apple's "Back to My Mac" remote connectivity technology, fixes SMB (windows file sharing) bugs, and fixes minor issues with the Mac App Store that appeared in OS X 10.6.6.
Beyond bugs and features, the update addresses numerous security concerns and flaws with built-in services, Apple's "Core" technologies, system utilities, and core details such as the kernel and filesystem handling. As with most security concerns, these were for issues where users could gain access to restricted files, cause arbitrary code execution, or otherwise change the system's configuration without proper authorization. Details on these can be found in this knowledgebase document.
As always, be sure to fully back up your system before applying this update. Ensure you have a full and restorable backup of your system, and have addressed current issues with your system. Optionally you can run a general maintenance routine and unplug peripheral devices before updating your system. For more details on preparing for an OS X update, see this article.