Problems with IV FW1.0.6

I am still using FW 1.0.4 which my MkIV came with and never experienced any problems with it at all.... in fact i was chasing a pervert yesterday and he was running away from me at quite high speed (receding) and it focused perfectly.

Now i am reading that FW 1.0.6 is actually causing a few issues, is this the case with one or many IV users??

Im not inclined to upgrade seeing as i have never had any issues with 1.0.4

What do you think ??