Full support for IMAP Folder setting

ian · August 14, 2026, 11:36am

There are too many discussions about this to pick just one, but you should probably start by going through the following:

github.com/chatmail/core

Remove `mvbox_move` and `only_fetch_mvbox` options

opened 03:27AM - 23 Dec 25 UTC

closed 04:42PM - 16 Apr 26 UTC

link2xt

These two options are "legacy options" that exist to support "shared mailbox" us…age similar to "show_emails" (https://github.com/chatmail/core/issues/7631). We currently have no plan on how we want to remove these options. We need a migration plan for two cases: `mvbox_move=1`, `only_fetch_mvbox=0` and `only_fetch_mvbox=1`. In case of `mvbox_move=1` and `only_fetch_mvbox=0` we can probably add a device message warning about the upcoming change and then turn off the option. If by this time we already solve #7631 somehow, then the user can solve the problem of cluttered inbox by adding a second relay and migrating there. For `only_fetch_mvbox=1` it is a bit more complicated as it is used to support the "alias" usecase, see here: https://support.delta.chat/t/it-may-be-unobvious-that-the-deltachat-folder-use-case-is-going-away/4495 If we want to support this for servers where user has access to configuring an alias and adding a sieve filter that moves messages with `Delivered-To` set to this alias to a separate folder, we can make a per-transport option "folder" and just run the inbox loop on this folder. I am looking at the current implementation of `only_fetch_mvbox` and it seems to be very hacky: we still maintain connection to the inbox, but then `should_ignore_folder` returns `false` for the inbox and it is ignored. Rough plan: 1. Add device message for users with `mvbox_move=1` and `only_fetch_mvbox=0` that the option is deprecated. Not as a migration, just somewhere after opening the database or in housekeeping or so. 2. Maybe one release later: turn `mvbox_move=0` off and remove all the code that allows running multiple IMAP connections. Instead run a single IMAP loop, either on the Inbox or on "DeltaChat" folder if `only_fetch_mvbox=1` is on. At this point users still cannot add second relay if `only_fetch_mvbox=1` is on. 3. Turn `only_fetch_mvbox` into a "folder" option in the advanced settings of the relay. Maybe make it unchangable in the UI so users cannot configure new relays in such a way, but code-wise it is probably not a big deal to support.