I'd widen that to "I don't want to use outlook" which includes Linux installs but also all thunderbird windows users, I'd think.

Yes, as a long time Thunderbird on Windows user I second this.

Thunderbird is frankly the only Windows email client worth using if you do any development using email. The tools available as add-ons simply aren't so readily available for other options, especially not for free.

"my work uses exchange on-prem" is pretty large though, especially in headcount (enterprises).

I don't know of any published numbers about specific user count (would be very interested to see them), but in terms of deployments it's gone from more than half on prem in 2018 to ~16% in 2023. Of that 16%, I wonder how many users are both willing and able to use an alternate client?

Of the organizations that have Exchange Server on premises, I'd bet the lions share are hybrid, with regular user mailboxes in the cloud, using the server(s) for application relays, etc.

I'm a Thunderbird-on-Windows-in-VM-on-Mac user for one on-prem and one web-but-can't-access-on-non-managed-windows-endpoint VM account.

And yet it's exactly the situation I'm in. I use evolution on Ubuntu through a horizon virtual desktop, purely for better exchange support. I switched from thunderbird on windows to outlook on windows when I started having a lot more meetings to coordinate, and then evolution when a virtual desktop solution was rolled out and Linux was an option for desktops at work again. Quite a few other people in my department that just use thunderbird on Linux because they can't stand outlook or using the web version would happily have better outlook support.

Perhaps there is an audience here and it just doesn't match your own experiences.

Does evolution calendar work seamlessly with Exchange? I used Thunderbird with the Exchange addon for three years and email and contacts worked without any problems, but calendar was bad. I could see my calendar but couldn't edit it from Thunderbird.

Not seamlessly. It seems to work but is half-broken. Id does not properly pair invitations, updates and RSVPs from emails with auto-created items (by the Exchange server) and you end up with duplicates and mess. At leas that was my experience when I used this setup. Then moved to evolution for email and web outlook exclusively for calendar. Now I am on windows partly for lack of proper Outlook and Teams on linux (sad).

I’m not sure what you are talking about. When did I say where I was in that venn?

I am Linux Desktop and hate outlook web.

I am the target user, and the post about Rust and using EWS gives me almost no confidence in this.

And I’m more aware that my case isn’t popular, and targeting on-premise is even less so.

Email solutions are company-wide, and companies are big.

Tons of companies use exchange on-prem either for historical reasons or legal reasons (e.g. they can't store email in the cloud - yes, this is very much a thing).

Beyond a certain size, companies inevitably have to support teams on different OSes. You have to let the accounting and finance guys use Windows (they'll die without Excel), you have to let the creatives use OSX or they'll throw a fit, and you have to let some in house IT teams use Linux.

But they all have to use the same email platform, and if it's on-prem exchange, the Linux guys are in a tough spot.

> I think they’re making a mistake using EWS

In 2024.

Should they did it in 2012 the people would actually use it. For now - yes, anyone needing a thick mail client for Exchnage but not Outlook has figured their workarounds years ago.