Internet Calendar Subscription

Hi all,

I just migrated from Zimbra to Carbonio. Everything worked smooth.

When I wanted to subscribe to an external ics-calender, I recognized that this feature seems not be implemented in the current version 26.3.0. This is a show stopper for me. Therefore my questions:

1. Is this feature not implemented yet?
2. Are the plans to implement it? Any roadmap?
3. Are there workarounds (e.g. CLI commands) to have it under the hood without the WebUI?

What other alternatives exists to Zimbra in the open source space?

Best regards,
Elmar