Calendar and Virtualmin Email

[vander.host]

SYSTEM INFORMATION
OS type and version	Ubuntu 20.04.5 LTS
Webmin version	2.001
Virtualmin version	7.3-1 Pro
Related packages	Roundcube, Usermin, Virtualmin Pro version

I need advice on calendar integration. As some clients’ needs mature they ask us:

We are using your email, it’s great. But we notice our calendar’s don’t sync. How can we have our calendar sync from our desktop to our phone?

I understand how Caldav works. I understand I need a Caldav server.
I’ve used calendar’s across Outlook using Microsoft 365 and it just kinda works.
But I can’t refer my clients to Microsoft 365 because it’s business lost forever.

When you start looking for something like Usermin or Roundcube and calendar and Virtualmin it appears there is a black hole. Good reliable information is hard to come by.

Roundcube"plus" has a calendar plugin for $45. Does anyone have experience with it? If I buy it, can I enable it for more than one domain? At this point paying $45 is a lot better than loosing some of my key clients. And then what does this mean in Roundcubeplus page?

7. Even sharing might not work when using Roundcube on Webmin, since on Webmin Roundcube user names might not match user email addresses because I’m not trying to share events, rather just enable calendar’s for users across two devices?

Perhaps the above sentence therefor doesn’t matter?

Please note I don’t have to use Roundcube or Usermin I just need a solution.

I see WHM /cPanel has a solution which of course involves a Caldav server. It uses Z-Push like Kopano does. This would imply a whole new technology and setup and then this ominous warning when installing:

This plugin has a recommended minimum of 7 GB of RAM, but your server only has 5.8 GB. Your server may experience performance issues while using this plugin.

So far to me it looks like the final stranglehold Microsoft and Google has on groupware is that getting calendar integration working in a modern mobile and desktop environment is that open source isn’t available for that solution.

Any ideas from the community?

[dimitrist]

using nextcloud for calendars/contacts/files/mail attachments and many other stuff… syncs both-ways from mobile/desktop and can be exported into roundcube as well, without any issues. you can setup your own nextcloud instance (self host) or rent some space in a nextcloud provider. lots of those available…

if you’re ok with one-way sync, then roundcube offers free calendar plugin, that exports a read-only .ics url you can use in desktop/mobile clients. calendar updates from within roundcube only…
didn’t know about roundcubeplus but at first glance it seems it’s sort of the same plugin as the free one. (read-only for other calendar clients , export/import.)