MAIL AND DIRECTORY MIGRATION
Adding users to a 'migration' group
Before migrating users, consider creating a Notes group, called MigratedUsers, and adding everyone you migrate to this group during registration. Creating such a group provides you with an easy way of identifying migrated users later on, when sending out upgrade notification messages or other information related to the migration.

For more information about sending an upgrade notification message, see the topic Sending users an upgrade notification message.