Understanding Best Methods, and Their Benefits, for Connecting to Exchange Online


This article describes the benefits of using the Messaging Application Programming Interface (MAPI) connection with Exchange Online and the operating system/client combinations that support it.


Microsoft Exchange Online is a cloud-based email and calendaring service that is part of Microsoft 365. It offers a dependable, secure, and collaborative way to manage email, calendar, contacts, and room resources. In 2016, the university shifted from Exchange on-premises to Exchange Online to leverage the scalability and security of the cloud service. In 2023 to 2024, the university shifted all email users except alumni to Exchange Online.
To take full advantage of Exchange Online, desktop users will need to use a supported Messaging Application Programming Interface (MAPI)-capable email client. The following lists which operating system/email client combinations best support the advanced features and functionalities of Microsoft Exchange Online:

  • All operating systems (major web browsers): Outlook on the web (OWA, https://outlook.office.com/)
  • Windows: Outlook, Windows Mail
  • Mac: Outlook for Mac, Apple Mail

Mobile (using the Exchange ActiveSync connection method):

  • Android: Outlook mobile app (OMA), Gmail app
  • iOS: Outlook mobile app, Apple Mail

As of the shift to Exchange Online in 2016, Virginia Tech discontinued the Internet Message Access Protocol (IMAP) and Post Office Protocol Version 3 (POP3) services in the Exchange Online environment with no plans to re-enable them. The supported Outlook email clients using the MAPI connection method provide benefits over the more basic IMAP or POP3 connection methods, including:

  1. Performance and synchronization improvements: With direct server-to-client communication users will experience less delays in receiving messages and better synchronization.
  2. Enhanced support and management: Supporting consistent configurations across MAPI clients can improve security, compliance, and centralized management.
  3. Security: using MAPI clients ensures support of advanced security features like integrated multi-factor authentication (MFA) and best security policy practices including data-loss prevention (DLP) mechanisms.
  4. Advanced integration: these clients also offer more comprehensive integration with Microsoft's ecosystem, including features like offline access, rich calendaring, and advanced mailbox capabilities.