I imagine the definition of "upgrade" depends on the needs of the customer. The merchant of the license is inherently unable to evaluate this. Installing software without explicit consent, especially not-functionally-equivalent-software, is inherently wrong.
It's amazing to me that we're all so chill about a company in Redmond having root access to our PCs because they pinky-swear they will never misuse it.
And yet when you call it what it is (a backdoor) people get highly offended. Same thing with ubuntu snaps or really anything that updates automatically.