Migrating Exchange mailboxes from one Exchange server to another is a common requirement that most of Exchange administrators have to deal with. MS Exchange allows moving mailboxes from one Exchange server to another if both source and destination servers are members of the same Organization and Administrative Group. Another criterion is that destination servers must belong to the same version as the source server or a higher Exchange version.
As far as migration itself is concerned, it can be achieved by simply copy-paste operation between source and destination server. You can copy the mailbox database and paste it in the destination server’s storage group. In this case you will be required to re-create the links between mailboxes and Active Directory user accounts after copying the mailbox database.