You cannot actually call it a migration, because the Outlook Add-in is identical for Jira Cloud and Jira Server/Data Center. The only steps you need to take are:
Install the related Jira Cloud App of “Outlook Connector for Jira”
Change the connection settings in the Outook Client. Or add a new connection, then you can use Jira Data Center and Jira Cloud at the same time.
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