Tick Tock version numbers

[Francisco Reyes]

I have a small, 3 machine, cluster with 3.2.1

Can I upgrade them to 3.6 from 3.2? Or is it advisable to upgrade to 
each intermediary version?

Based on what I have gather seems like it is matter of:
bring node down
install new version
bring up
run nodetool upgradesstables -a

Is that the correct process?