Some people use software term some people use firmware term.
You can put latest S/W 0040 but I recommend to be on the save side and use S/W 0020 because nobody really knows what index will be present on upcoming US DVD. If it's 0040 you could be stuck without possibility of upgrade (if that wil be possible for EU units at all)
Software is stored on a disc, firmware gets programmed into a memory chip.
So on your PC at home the BIOS is firmware (it gets programmed into the CMOS memory), and the operating system (Windows, Linux, ...) is software (it's permanent home is on a disc) - RAM doesn't count since its contents disappear when you turn the power off.