I did the update as well no problem
what I did notice while on there was the annoying statement concerning the LCD panel when illuminated in extremely dark environments, the displayed exposure value may change. Canon has decided on our service policy to address this phenomenon, so we would like to inform you of the details as described below.
Affected Products
EOS 5D Mark III Digital SLR Camera whose sixth digit in the serial number is 1 or 2.
For example, xxxxx1xxxxxx or xxxxx2xxxxxx (x represents any optional number)
Just so happens mine has a 1 in it boo hoo
but then how many times will I be in the pitch dark pressing the illumination button and focusing
think I may just leave it , as they are asking to send it to the canon dealers to get it checked and fixed...Any of you guy's in the same boat