As someone running their own mail server, I find that way too few people are running their own mail servers.
Because of the way the email ecosystem has been set up today you can be sure your email will never arrive for half your recipients unless you pay Google or Microsoft for letting your mail pass through your servers. Everything else gets marked as spam, dropped during transit or just plainly disappears into a black hole when sending mail to Gmail or Outlook.
There are many mail server projects for personal or small business use (take Mail-In-A-Box or SoGo for example) that are easy and secure to set up. There's some fiddling with DNS to be done but anyone with an hour of free time and access to Google can set all of that up correctly in no time.
To keep Google, Microsoft, Apple (and the competing Asian companies) from gaining even more power, more centralisation is not the solution.
You can look into SOGo which use the CalDAV protocol and is compatible with Thunderbird's Lightning and DAVdroid. You can use any server you want to host, either a trusted server (I use my Posteo account) or a self-hosted server (see NextCloud).
Looks very exciting!!
How do you plan to convince existing Microsoft Teams/Slack/Zoom/[other proprietary app] users (or those considering using Teams) to switch to Twake?
And how does Twake compare to other open source solutions like Element which uses the Matrix protocol for team chat or the SoGo groupware server?
Honest question because I hope you can succeed in creating a 100% free as in freedom replacement for Microsoft Teams!
Since you mentioned Evolution, I assume you're looking for a mail client that supports CalDAV/CardDAV rather than a filesystem interface for WebDAV (which Windows Explorer supports natively).
Thunderbird can support CalDAV and CardDAV sync on all platforms via the SoGo connector extension.
I don't like the nextcloud mail client nor rainloop. They are very...rudimentary. Sogo is, in my opinion, by far the best webmailer, with support for calendars, contacts and provides caldav/carddav/active sync interfaces to sync with all kinds of clients
Super easy setup, SOGo for it's webmail (prettier and mobile friendly), helps walk you through things like SPF and DKIM so you don't get blocked by spam filters, and SOGo supports S/MIME so you can send encrypted emails, as well as connect it to external email accounts.
SoGo - https://sogo.nu/I have never used it myself, but I've seen it in practice and it seems quite nice. It also provides Active Sync for people who like to use Outlook or a phone.
sogo.nu might be an alternative to Nextcloud if you plan is to use it to host email, calendar, tasks and contacts. The only thing so far it doesn't do is taking notes, but you could basically send an email to yourself.
I've been using SOGo, self-hosted with Docker and proxied behind Traefik 1.7, and it's been very good for this. It's commercially-supported GPL: inverse.ca took over as the main developer some time ago, prettied it up substantially (earlier versions were capable but butt-ugly) and they sell installation and support packages, mainly to governments and non-profits. So its longevity seems assured in the medium-term.
SOGo has one unforgivable flaw, which is that it doesn't support STARTTLS, so no port 587. I self-host my email, so I got around this by opening a separate port (588), only on the private Docker network shared by the mail server and by SOGo, on which SOGo sends mail. That port isn't even visible from the host OS, so that's a workable solution for me, for now. I opted for that workaround because the whole system is otherwise functional, stable, and pretty. Search is fast. Calendar sync with DAVx5 to my Android device is flawless. And so on. But it's important to be aware of this shortcoming.
There is...kind of
Sogo is opensource and standards compliant groupware. It has a server that offers ActiveSync, and several clients including 2 options for Thunderbird plugins that enable ActiveSync. I haven't tried it as a standalone ActiveSync Client but it may be worth a look.
> It's not official so does it matter
A few projects (SOGo e.g.) outside GNUStep itself are using it, yes.
> why would you want to?
No idea, I haven't used ObjC myself.