WD20EARS-00MVWB0 firmware upgrade?

I have some hard –disk that were brought by me dad as well as my brother at the same time so now I have two   WD20EARS-00MVWB0so I have been trying to run SMART on this , but the problem that I have been facing here is the fact that this two hard-disk have different firmware version so can  is it possible for me to upgrade the firmware so that both of them would have the same hardware .