This is the new Version 6.4, released 9/30/11 to fix the Internet access bug in Version 6.2.
If you are not using Internet access, there's no need to upgrade.

ABOUT STUDENT PROGRAMS. If you are:
 an instructor: Configuration required before distributing these to students.
 a student with an instructor: Please ask your instructor before downloading these.
 a student working alone: These are for you to download and install.

CLICK HERE TO DOWNLOAD THE LATEST COMPLETE INSTALLERS:

Download INSTALLxyAlg64.exe: program to install xyAlgebra 6.4,
  which provides instruction and practice in basic algebra
Download INSTALLxySol64.exe: program to install xySolver 6.4,
  which provides instruction and practice in solving verbal problems.

Then run the installers to install the programs.
Look for the installers in your Downloads folder if no download location was requested.
See also: Topic Coverage for each of the above student programs.