I updated one of my two a-1 bodies from 1.32 to 2.01 with trepidation. The camera is definitely warmer during operation with the new Firmware. AF on flying birds in crummy conditions with the 600 f/4/1.4X TC combo. As I have the 300mm f/2.8, I rarely use the 200-600 any more. Battery life seems poorer as well.