Does enabling encryption on vSAN require on an-disk format change?

vSAN 6.6 shipped earlier this year. It comes with a new on-disk format to support, among other things, data at rest encryption (also known as DARE). This is version 5 of the on-disk format. I’ve been asked this question a number of times over the past week, so I thought I would quickly write a few words on whether or not enabling encryption on vSAN 6.6 requires an on-disk format change, more commonly referred to as a DFC. Now this post is not going to cover vSAN encryption in any great detail; I just want to answer this one question…