No notes on what the patch is at the moment and the forums are down but the Steam forums are speculating it is the LAA patch:
http://forums.steampowered.com/forums/showthread.php?t=2306904
Nothing official though.
One player said:
Regardless you may want to hold off patching till more news.
http://forums.steampowered.com/forums/showthread.php?t=2306904
Nothing official though.
One player said:
Just checked in CFF explorer. It's marked as being able to handle >2GB addresses (The LAA bit is set). So yeah, 4GB patch.
Regardless you may want to hold off patching till more news.