In the announcement of the most recent set of Cumulative Updates for Exchange Server 2019 and 2016, Microsoft introduced some changes – features if you will – as well, which were received with enthusiasm. An overview of these Cumulative Updates and the features introduced was given in an earlier article. In this article however, I would like to zoom in on one of those features, which also happens to be a popular topic among customers running Exchange Hybrid deployments, “The Last Exchange Server”.
Up to Exchange 2019 CU12 (2022 H1), customers that migrated to Exchange Online were still required to leave Exchange-related components running on-premises. Even today, with all the information published around this topic, I am surprised this still surprised customers. This Exchange server running on-premises is to be used for managing recipients which have their source of authority in Active Directory, leveraging Active Directory Connect to propagate objects to Azure Active Directory and thus Exchange Online. Also, when there is a need to relay messages from applications or multi-functional devices, customers often need to have an Exchange server on-premises to accept these messages, as Exchange is the only supported mail relay product for hybrid deployments.