You Joke?
Seriously. EMC employees trying to justify this are only making it worse. It's a joke.
Nutanix upgrades it's software routinely during business operations. Before someone comments about the magnitude of this XtremIO code release, Nutanix changed their OS in their CVM a while back, non-disruptively, nobody noticed.
EMC, just come out, admit all your sales guys misrepresented the solution with respect to never needing a disruptive upgrade, apologise, and ensure that if your customers do it and stay with you now, whatever you deliver ensures they never have to do it again!