What is Freebsd 7.2pX

[David Southwell]

Where is information about 7.2pX to be found on freebsd.org?

I am running freebsd 7.2 64 amd 

7.2-RELEASE #0: Fri May  1 07:18:07 UTC 2009     
root at driscoll.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64

version on Intel quad core and was advised to upgrade to 7.2pX but have 
not found about such a version from the web site and a google search for 
freebsd 7.2pX produces no documents.

Thanks in advance

David