I've recently purchased 2 used units. An 1198 & 998 and the current software versions for both are 7.510...looks like the most up to date version for both is 7.670...Is there a version(s) between these that I need to update to first before jumping to the 7.670? What do I need to do to update?....create an account and then update? I bought an 8 GB SDHC card...will that work? Thanks, Mike