Why isn't version 16.1.0.33 available to everyone??

It looks like 16.1.0.33 has been available for at least several months now.  I'm new to Norton.  I installed NIS 2009 in September.  The version I have is 16.0.0.125.  First of all, I don't understand why Norton didn't give me the new version to install.  But more importantly, why isn't 16.1.0.33 available to everyone now??