Multiple hits and mail sorting?

Question

Exim

Hello!
There is a mail domain and users. It so happened historically that the mail domain runs on a unix server (opensuse + xams) with MTA exim. Users have historically set up the same mailboxes on 2-5 clients and read the same mail together using MS Outlook. For example, a letter to the [email protected] box arrives in the imap box and everyone who is configured to receive this mail on their clients will see this letter in their Inbox. Everyone is used to it and works and everyone is comfortable. If someone is busy or sick, another employee will quickly respond to the letter.
But the need has come to sort letters into folders on the server. So that letters from one sender still on the server get into the selected folder for this sender. And so that all active users can immediately see this selected letter in the right folder.
Sorting by means of Outlook is not suitable because there are cases when someone is not online or the PC is turned off and if every one of the five mail readers does this, then it seems that there may be problems with duplication, etc., etc.
On the current server, this is difficult to implement beautifully due to the intricacies of the current Exim setup.
So the options are:
1. drag mail to Yandex.Mail and get rid of the server in principle. But here there is a fear that when users come in the morning they can re-download their old letters (and these are not small volumes).
2. Search how to enable sieve in xams. But this option may later come out with another rake or break something that is already normal and works that way.
Please advise another solution, more elegant or comment on my solutions.
Thanks in advance!

Answer 1

If the imap server is dovecot, then it has support for sieve, which has nothing to do with Exim. But here I see one problem - this is a check by the mail client of third-party folders. Outlook, as Dmitry Shitskov quite rightly noted here , only checks Inbox, so he simply will not see new letters in some left folder, unless you find some kind of add-on.
In addition, sieve filters will have to be written manually - because there is no sieve support in Outlook and is not expected.

Answer 2

Don't touch anything on MTA, use Outlook's Search Folders.

Answer 3

Sort by means of the IMAP server, namely sieve / managesieve.
No problem.