My understanding is that “no style” isn’t a style, but an absence of one, and therefore, you can’t set “no style” to have particular attributes. I base my understanding of this aspect of Scrivener not only on the basis of conversations, but also because if you select text that has “no style”, change the font face and/or size, select that text, and then go to Format->Style->Redefine Style From Selection, you won’t find “No Style” in the list of styles that you can re-define.
Instead, new documents inherit the font and paragraph settings from how you set things up in File->Options->Editing->Formatting or Project->Project Settings->Formatting for a given project if you want it to differ from the global settings.
I’m not sure what’s supposed to happen when you paste in text using “Paste and Match Style” into a paragraph that has “No Style” and/or what’s supposed to happen when you apply a style that includes a font face and then remove that assignment of the style, returning it to not having a style (aka: “No Style”). I figure that manipulating text in this way does probably complicate these questions though.
So, I’d suggest you explain how it is that you think you set “No Style” to a particular font, and now that you’ve upgraded, what is it that’s showing you that this “setting” is gone? For instance, did your entire project change all unstyled text (aka: No Style) to Calibri, or is this just for text in new documents you’ve created?
If you edit a document that was in your preferred font before the upgrade, is that font still set to the “No Style” text, or was it changed?
If you add text to that document, does the new text follow that font setting, or does it appear to have been reset?
Also, after re-loading your preferences/settings, did it preserve what you had set in the Formatting sections of settings (see the menu paths above)?