You can find more information about the Connector in the Exchange Administrator's Guide. Mail is available in Exchange Server 5.5 Service Pack 4 . Support file attachments in both directions. Support message fidelity such as message priority and read-receipt in both directions.
Some organizations adopt a slow pace with system migration, working out issues of coexistence.
Other organizations migrate quickly, minimizing the coexistence timeframe and disruption to the business. From a project-planning standpoint, it is necessary to perform migrations quickly and focus on ways to optimize a rapid deployment rather than spend too much time on coexistence issues. Mail directories, greatly reducing the directory administration. You can select this container during migration, which automatically converts the custom recipient directory entries to Exchange mailboxes. Since Microsoft Exchange Server 4.0 does not support the Connector, you must install an Exchange 5.5 server in the site.