The script are here
http://wiki.freepbx.org/display/PPS/FreePBX-Distro-6.12.65
and here
http://wiki.freepbx.org/display/PPS/FreePBX-Distro-10.13.66
I would suggest you make a backup before upgrading, whichever path you chose...
Good luck and have a nice day!
Nick