The Supplemental Update is for any system that was updated from Mac OS X v10.6 using the Mac OS X Update Combined v10.6.3, build 10D573. It is not needed on systems that were updated from Mac OS X v10.6.1 or 10.6.2, and it is not needed on systems that were updated from Mac OS X v10.6 using the Mac OS X Update Combined v10.6.3, v1.1.The Supplemental Update is for any system that was updated from Mac OS X v10.6 using the Mac OS X Update Combined v10.6.3, build 10D573. It is not needed on systems that were updated from Mac OS X v10.6.1 or 10.6.2, and it is not needed on systems that were updated from Mac OS X v10.6 using the Mac OS X Update Combined v10.6.3, v1.1.