firmware is a software for you hardware in this case your burner.
When new release of firmware come out they tend to B bug fixes and more media support updates, but not always a good idea to update just because a new verison is out.
Most times you can get them from the homepage in your case Sony...or forums like ourself. Word of warning backup your old firmware B4 hand incase the new one give's problems...

Try this site for
firmware for firmware...dvd roms, burners etc