Ask HN: A feature update newsletter to app users?

So if you think about a complicated application like Microsoft Excel, how do people learn that for the first time?

If you're coming from Microsoft's side, and you're getting it integrated in some company, would a person go there/do some kind of group presentation and present it?

We're currently doing that, although trying to make the onboarding self-explanatory, make PDFs (how-to guides), videos, things like that.

But if you wanted to inform users of known issues, feature updates as they come out... is something like an email weird?

I know some apps you get an in-app popup about features, maybe you can get fancy and do the feature highlights... however our app is not a leisure type use. If you use it you're directly connecting two people eg. user/their customer.

So I've been trying to think of ways to make that process more legit. This way people can gradually add on the new features that come out to their existing knowledge of the application itself.