Modern HTML email (tables no longer required)

Outlook on Windows has very much been the Internet Explorer of email clients. The Outlook desktop app on Windows, along with the Windows Mail app, were the only reason developers had to continue building emails with HTML tables. (Outlook apps on macOS, iOS, and Android are unproblematic.)

[...]

Tables within tables within tables...

It's well past time that Outlook got a proper update, and it's finally here. The new Outlook switches rendering engines from Microsoft Word to Edge. Support for CSS features in the new Outlook application appears to be identical to that of outlook.com, which is a great leap forward.

I had to read that quite a few times before I really internalised that yes, Outlook for Windows used Microsoft Word to render HTML emails.