Sony has released a mandatory PS3 firmware update, meaning you’ll have to download and install the patch before using your console the next time you boot it up.
According to Sony Japan, the main function of the new patch is “in system software [and] improved stability of motion.” In other words, system stability. Google translate must have bungled the language used there. The patch will also strengthen various security features of the console, while adding new ones.
So nothing that should take too long with decent internet speeds, then. Carry on.