If the system didn't experienced any kind of reboot issue or the computer is running great, I would suggest not updating BIOS at this time. You should wait to see if other users of that particular model complain about the new BIOS update causing problems. However, if you still wants to update at your own risk, please watch Dell video to safety installed latest BIOS version in link below.
Warning: Do not turn off your computer or disconnect from your power source while updating the BIOS or you may harm your computer. During the update, your computer will restart and you will briefly see a black screen.