remote-mailboxes

Remote mailboxes in hybrid Exchange deployments traditionally required an on-premises Exchange server to manage recipient attributes. Microsoft's new cloud-managed remote mailbox capability changes this by introducing the IsExchangeCloudManaged switch, which transfers the Source of Authority for Exchange-specific attributes from on-premises Active Directory to Exchange Online. This allows organizations to edit email addresses, proxyAddresses, and mailbox settings directly in the cloud without maintaining an on-premises Exchange server solely for recipient management. The feature provides a supported, auditable path to decommission the last Exchange server in hybrid environments while preserving identity attributes like name and UPN in local AD.