I checked their website for cpu support.
The only bios available for the board is F1. This is the first release bios. The website also states that the 6300 is supported under F1 bios.
I looked at a few other motherboards and the warning message is on all of the boards I looked at.
As far as I can determine from their website the 6300 is supported on that board from the start. Meaning no need to update the bios.