Didn't work for me
First image is P-TTL with 1.02
Second is manual with 1.21
Third image is P-TTL with 1.21
No discernible difference between 1.02 and 1.21 in terms of lag but huge difference between manual and P-TTL regardless of firmware version. Still way too slow in P-TTL to capture 'spur of the moment' shots, which is when I need P-TTL most.
Not sure what's happening with the exposure probably nothing to do with the firmware upgrade - possibly inadvertently different orientation of the flash head before and after the update.