Can someone help, when adding a new switch to an existing FC fabric is the recommendation that the switches should both be on the same level of firmware ?
our current switches are running 6.4.3 and the new switch is running 7.20a
our plan is to upgrade the existing 6.4.3 switches to 7.20a but is this necessary ?
Necessary perhaps not, but it could be recommended to upgrade anyway.
It all depends on which models you are using and what the vendor matrix suggests you should have
If you're planning to update the existing switches soon (in a couple of weeks) to FOS 7.x i personally would leave the new switch at the 7.x firmware. Its recommended/best practice to have all switches in a fabric running the same FOS version.
FYI you can only upgrade 8G switches to FOS v7.x.