How to transfer corporate mail to Yandex or Google?

Question

Microsoft Exchange

Good evening everyone!
There was a question about disabling the old corporate mailer on Microsoft Exchange 2007, since most users use a different server. But, as you know, there will always be conservatives and opponents. There are a couple of such people, and I consider it not very advisable to keep an extra server in the rack for their sake. In this regard, the question, can someone tell the thread whether it is possible to transfer the corporate mail of several people to the Yandex or Google servers without losing their entire long-term archive of correspondence? I know about the fact that you can link a mail domain to Yandex or Google, but here's what to do with user archives, files like PST and others.
I ask for advice from experts on how best to proceed. To make it easier, more reliable and ... for free :)

Answer 1

Yandex.Mail has a mailbox import.
Imported many times. Read more: here

Answer 2

Google seems to have run out of freebies https://www.google.com/intx/ru/work/apps/business/