Using a group for calendar sharing without a shared mailbox

[benalbrecht]

I am trying to set up a shared calendar for a group of ~10 users in Stalwart, but I'm running into an issue where an unwanted IMAP mailbox is appearing for all members.

• I Created a group (shared1) to act as the resource container.
• The group does not have an email address assigned.
• Users are added as members so they can access the shared CalDAV calendar.

Sharing the calendar works perfectly, but every user in that group now sees a new directory structure in their IMAP client under Shared Folders/shared1/. It includes INBOX, Sent Items, etc.
Since this group is only intended for calendar coordination, I want to hide or disable these IMAP folders entirely.

What I’ve tried so far:

• Disabling Mail Permissions: I attempted to strip all mail-related permissions from the group in the settings, but the mailbox remains visible.
• IMAP DELETEACL: I connected via IMAP to manually send DELETEACL for specific users on those folders. The server returns OK, but a subsequent GETACL shows the permissions are still there (they seem to be "ghosting" back or are implicitly re-applied by the group membership).
• IMAP SETACL "" : This returns BAD At least one right has to be specified, so I cannot nullify the rights that way.

Is such a configuration supported at all, is this a bug or on the roadmap?
Or do i need to figure out another way like setting ACLs for all individual users without relying on a group?

[mdecimus]

Unfortunately that can't be disabled but could be an enhancement request if enough users are interested.

[benalbrecht]

understood, i've changed the category to feature requests :)

[benalbrecht]

wrote a small imap proxy as a workaround: https://github.com/benalbrecht/imap-shadow