CS4 Process version

I am making photos for a client, and processing them in Camera Raw.  The client will be getting the files, and further process them according to their needs.  The client is using Creative Suite CS4.

How is Camera Raw being updated in CS4?  Will the client be able to use the current Camera Raw process, or will I need to use an earlier process?  Which is the latest process that has been updated to CS4 --  2010?  2012?