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Provide Feedback on Calendaring for the next version of Outlook and Exchange

Microsoft recognizes that enabling interoperability between products from different vendors is important, particularly with respect to email and calendaring functionality, as it helps our customers stay connected and organized across their favorite services and devices.

Exchange Server 2016 and Microsoft Outlook 2016 support the following core and most commonly adopted email and calendaring standards:

  • IMAP (Internet Message Access Protocol - RFC 3501): IMAP allows a client to access and manipulate electronic mail messages on a server. This protocol allows Exchange users to access their email across a broad range of IMAP clients and enables Outlook users to access email on IMAP servers.
  • POP3 (Post Office Protocol version 3 - RFC 1939): POP3 is a broadly adopted standard for webmail service providers. Outlook uses the POP3 protocol to retrieve messages from the server. The POP3 service for Microsoft Exchange Server is used by clients that implement the POP3 protocol to store and retrieve messages on the server.
  • iCalendar (RFC 2445, RFC 2446, RFC 2447): This common format facilitates the open exchange of calendaring and scheduling information across the Internet. iCalendar is supported by both Outlook and Exchange and enables syncing and publishing of calendar items across supported services and servers, regardless of platform.

Extensive documentation of this support is publicly available at no charge on MSDN. Microsoft will continue to support these standards in the next versions of Exchange Server and Microsoft Outlook.

To ensure that Microsoft continues to invest in the standards that are most valued by our customers, your feedback is essential. You can tell us what email and calendaring standards you’d like to see in the next versions of Exchange Server and Microsoft Outlook by sending an email to, tweeting us at @OSpecifications, posting to our forums here, or attending an interoperability event. (Note: please do not include confidential information in your feedback.)

Check back on the blog in 90 days, when we’ll post a general response in this forum. Thank you in advance for your valuable input.