Thank you for sharing this. I still hope it is a temporary situation.
Any idea, which mail app to use for Nextcloud?
The standard “mail” app cannot do HTML mails.
The Roundcube webmail is not easy to install and does not really help, as we already have Roundcube webmail outside of Nextcloud.
We use at the moment Rainloop - it works, but we hope to find a more modern mail app soon.
First of all, you really shouldn’t use Rainloop anymore, especially if it’s exposed to the internet, since it hasn’t been maintained in years and therefore no longer receives security updates.
Other than that, there really aren’t that many open-source and self-hostable webmail clients out there, let alone modern ones that are more or less feature-complete. I’d say, you’ve already mentioned pretty much all of them in your post.
Besides Roundcube, which you already mentioned, there’s also AfterLogic WebMail Lite, which has an integration app for Nextcloud. Like SnappyMail, it’s based on Rainloop, but the “Lite” in the name suggests that it might not include all the features SnappyMail has, and that there’s a commercial Pro version with more features. I haven’t tried it myself though, so I can’t really say much about how complete it is feature-wise.
