Believe it or not, not everyone has a Microsoft Exchange messaging system within their environment. Although we are not focused on non-Exchange messaging systems, it's still an important topic when working towards an understanding of how to integrate with Office 365. The key items of focus for non-Exchange Messaging Systems are:
Active Directory readiness
Coexistence options
Migrating from a Non-Exchange messaging system
If you are managing a non-Exchange system, you already know that your Active Directory environment may not match your existing messaging environment. As an example, if you have Lotus Notes or GroupWise environments, these environments do not depend on Active Directory for authentication. Because of this, it's likely that your messaging users may not be an exact match to your Active Directory users. In fact, even if they match, the attributes may not look the same. When you plan to migrate a non-Exchange messaging system...