There are several BIOS revisions available in the ASUS webpage for that motherboard. However, changing the BIOS version, while safe if done correctly, can also lead to big problems if done wrong. New BIOS versions are made available when some hardware incompatibility has been detected that needs fixing. So, if you are not having any problems with your hardware as it is now, keep the BIOS version, just don't mess with the BIOS if it's not necessary.