A. Most organizations already have a mail system, so being able to migrate to Microsoft Online Services and coexist with the internal mail system is important. Microsoft provides tools to help migrate mailboxes from Microsoft Exchange Server and POP/IMAP services and let them coexist. When your local mail system coexists with Exchange online, mail comes to your internal mail system and is then forwarded to Microsoft Online Services for unknown recipients.

There's no free/busy synchronization currently available for internal-to-Microsoft Online Services systems, but the upcoming Exchange 14 should help in this area.

As part of Microsoft Online Services adoption, Microsoft will work with the company via a partner to help the migration. Other source mail platforms can be migrated to Microsoft Online Services using third party mail migration tools.

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