Upgrade path for TS4 build 18

["Nurudin Kaba" <nkaba@xxxxxxxxxxx>]

This is my first post to this list so here goes ... I would like to upgrade my TS4 Build 18, 
to include the Y2K patch and also update it to the most up to date build.  What file(s) do 
i need and where do I get them?  I would appreciate any help.  

Thanks
Nurudin