Migrate from Microsoft Exchange using GSMME
This feature isn't available in the legacy free edition of Google Apps.
Migrate your users' mail, contacts, and calendar data from a Microsoft® Exchange server using the G Suite Migration for Microsoft Exchange tool (or GSMME for short). You can also use GSMME to migrate mail from IMAP servers such as Novell GroupWise®, as well as from other Gmail accounts.
For complete instructions on using GSMME, see the GSMME Administration Guide (PDF).