Exchange Online

Exchange Online is a Microsoft-hosted messaging and collaboration service based on Exchange Server. New Exchange features appear first in Exchange Online, and some but not all are later offered in Exchange Server on-premises. Recent and planned improvements focus on supporting file sharing and threaded discussions through other Office 365 collaboration services (such as Office 365 Groups) and improving filtering, security, and archiving through add-on services. Mobile clients licensed with Exchange Online will also be an important priority.

What Is Exchange Online?

Exchange Online is a Microsoft-hosted messaging and collaboration service based on Exchange Server. The service, available with Office 365 subscriptions or separately, supports e-mail, calendars, contacts, and tasks; works with Exchange-compatible clients; and offers a Microsoft-hosted version of Outlook on the Web.

Most on-premises Exchange features, such as public folders, archiving, cross-mailbox search, and administration tools, are also supported, and Exchange Online can be used in a hybrid scenario alongside an on-premises Exchange deployment. Microsoft deploys the latest Exchange features to Exchange Online; some, but not all, are offered subsequently with new versions and updates to on-premises Exchange software. Exchange Server 2016, which became generally available in Oct. 2015, is the most recent on-premises offering.