Do i upgrade the Firepower management Center before or the actual Firepowers (FTDs) first?

FMC is running 6.2.3.13 FTDs are running 6.2.3.13

I assume I upgrade the FMC first, right?

Also can I just go to 6.4 or is it like the PA where I have to go to 6.3 and then 6.4

Thanks