Yes, but you are probably using a NTSC camera and not a PAL model (HVX202). I've been using the V4.05 firmware myself since it was released, but not with PAL.
I was responding to RE1000, who said he had that firmware. The point I was trying to make is that since he is in Boston, he is probably using the firmware for the HVX200 (NTSC) and not the one for the HVX202 (PAL).
I've been using the V4.05 firmware for the HVX200 since it came out with no problems, but I'd hate to tell you it's fine only to find out that there is a problem with the PAL cameras.
I haven't heard of any problems, I just don't want to mislead you.
I've found an issue when using the frame rate hack, which kind of scared me but it turns out to be nothing really.
Trying to use 25p on a US HVX, when I toggle over to the thumbnail screen it's glitched out. Have to power down and power back up (with a frame rate other than 25p selected!) in order to clear the issue up.
So it's my own fault, shouldn't be trying 25fps on a US HVX anyway, but that's the only thing I've found so far.
The best new thing is the Type 2 clip name feature.