[samuel-freeman]

Are you sure? I have a paid office subscription, and I use that Outlook. I switched to the New Outlook for Windows from the app (it was offered to me), and I took the screenshot from there.

I know the New Outlook for Mac is free now, and I heard about plans to make the New Outlook for Windows free as well (to replace Mail), but I didn't know about a different business version.

As far as I see, the New Outlook for Windows/Mac will be a web app in Electron or with similar technology, and the application that interacts with the IMAP/SMTP is actually on a server.

The add-ins for the New Outlook for Windows/Mac also do not support accessing anything local:

"Data sync service Enable bidirectional synchronization of mail items with partner systems. Partially supported. Essential features are yet to be addressed to create a similar experience to VSTO or COM add-ins."

The migration guide of older plugins (C#) they recommend moving common features to a shared module and then running that shared module in a Azure Cloud, since the only thing these web based plugins can do is http requests.

Edit: Source: https://learn.microsoft.com/en-us/office/dev/add-ins/outlook...