Apple today pulled the OS X 10.6.5 server update, though no reason was given for its removal.
The PowerMac G5 was the first system developed by Apple that came with a liquid cooling mechanism for the models with higher-clocked dual PowerPC chips. In most systems, this cooling system worked well. To this day, my system has not shown any problems; however, some systems had an issue where coolant leaked, causing corrosion and shorting out mainboard components.
Apple has released a security update (Security Update 2010-006) for OS X 10.6.4 Snow Leopard, which addresses a problem uncovered in the OS where a remote attacker could use a known username to access files in shared folders.