Hello, You can definitely update the BIOS to version A11.  Just ensure there are no peripherals connected to the computer other than the Battery and AC Adapter.  There are no risks at all in updating the BIOS.  Please refer the link mentioned below to download and install the latest BIOS version. [URL] You may also go through the tab for Fixes and Enhancements for the benefits in updating the BIOS to the latest version from the same link.  Please reply if you have any further questions. 
Hi, I am currently updating my drivers and would like to know if there are any risks if i install the A11 BIOS for my 15z. Currently it has the A06 BIOS.
BIOS