Apple released a full round of Mac OS X 10.6.6 updates in early January. Based on my research, I’ve concluded it’s safe to update to Mac OS X 10.6.6 on both Mac clients and Mac servers. In addition to the Mac App Store, the update includes a number of stability and security fixes. It also resolves DNS and related problems introduced by the Mac OS X Server 10.6.5 update (which I recommended server owners to hold off installing until Mac OS X Server 10.6.6 was released).