How to transfer mail from pdd.yandex.ru to your mail server?

Question

Yandex

There are corporate mail attached to the mail for the Yandex domain. For security reasons, you need to import all mailboxes with content to your company mail server.

Answer 1

A solution is selected, Exchange, Zimbra, Postfix, Exim, something else.
A plan is made for mail migration,
synchronization is set up using imap4, for example, the source and destination,
MX records are edited for a new domain at the same time,
users are transferred to a new server (local software connection, training, configuration)
Everything works for a couple of weeks, the last synchronization run is done, preferably more back up the original mailboxes, for example, to local pst, and throw them into storage.
Migration completed.