Hi!
I have a Cyrus IMAP server with several users which give me access to some of their IMAP folders by setting the IMAP folder ACL accordingly.
The Cyrus IMAP server is configured to use the dot (“.”) as path separator, mailboxes all are under the “user.” prefix, each users own mailbox is also usable with prefix “INBOX.” for this user.
In my IMAP desktop mail clients (e.g. Thunderbird for Linux or KMail) and also on Webmail applications like SOGo or NextCloud I see those folders shared with me in my folder list prefixed with “user.username” (e.g. “user.max”, “user.max.IMPORTANT”, “user.joe” and “user.joe.Sent”, …)
In the configuration settings of older versions of K9 mail for Android I always unchecked the checkbox for “Detect IMAP namespace automatically” and let the “IMAP prefix” input field empty. K9 mail then showed me all folders shared with me with the same path prefixes as my desktop mail programs. Exactly as I wanted!
In the more recent versions of K9 Mail (and also Thunderbird for Android) this does not work anymore!
Here, the initial account configuration already fails with an “can not read folder list” error if I uncheck the “Detect IMAP namespace automatically” checkbox. The initial configuration can only be finished successfully if this option is checked! But then I only see my own IMAP folders, not those shared with me.
When the initial configuration is finished I can enter the mail server configuration again and remove the tick from this checkbox.
And with “Detect IMAP namespace automatically” unchecked this way I tried several settings for the IMAP prefix:
- leave it empty
- A single blank
- A single “/” character
- A single “.”
- The string “user”
- The string “user.”
But none of them give me the functionality I want. I never see IMAP folders of other accounts which are shared with me.
Is this a bug or a configuration error on my side?
If it’s a config error: what is the correct way to set up K9 mail to see IMAP folders of other users shared with me (i.e. folders where I have at least read access due to ACL settings on the server side)?
Has anyone successfully configured a recent version of K9 Mail or Thunderbird for Android against Cyrus IMAP with shared mail folders, like I described here?
Thanks!