Upcoming changes to Exchange Web Services (EWS) API for Office 365

Office Add-ins team

Over the last few years, we have been investing in services that help developers access information in Office 365 in a simple and intuitive way. As we make progress on this journey , some technologies become obsolete and  they no longer provide the best way to interact with Office 365 data. Today we are sharing our plans for the roadmap of Exchange Web Services (EWS) and the planned deprecation of Basic Auth access for EWS in October 13th, 2020.   These plans apply only to the cloud-based Office 365/Exchange Online products; there are no changes to EWS capabilities of on-premises Exchange products.

Exchange Web Services will not receive feature updates

Exchange Web Services (EWS) was launched as a part of Microsoft Exchange 2007 as a SOAP based API that allows access to Exchange and Exchange Online data. Starting today, Exchange Web Services (EWS) will no longer receive feature updates. While the service will continue to receive security updates and certain non-security updates, product design and features will remain unchanged. This change also applies to the EWS SDKs for Java and .NET as well.

While we are no longer actively investing in it, EWS is still available and supported for use in production environments.  However, we strongly suggest migrating to Microsoft Graph to access Exchange Online data and gain access to the latest features and functionality.   For more information and details on how to make the transition, please refer to the following articles:

Overview of Microsoft Graph

Overview of Outlook mail API on Microsoft Graph

While EWS and Microsoft Graph have mostly overlapping functionality, there are some differences. If you rely on an EWS API that does not have a Microsoft Graph counterpart, please let us know via UserVoice of features needed for your app scenarios.

Basic Authentication for EWS will be decommissioned

Exchange Web Services (EWS) was launched with support for Basic Authentication. Over time, we’ve introduced OAuth 2.0 for authentication and authorization, which is a more secure and reliable way than Basic Authentication to access data. Please refer to the following article for more information:

Getting started with OAuth2 for Microsoft Graph

Today, we are announcing that on October 13th, 2020 we will stop supporting and fully decommission the Basic Authentication for EWS to access Exchange Online. This means that new or existing apps will not be able to use Basic Authentication when connecting to Exchange using EWS.

Next Steps

The deprecation of these APIs follows our service deprecation policies. We understand changes like this may cause some inconvenience, but we are confident it will ensure more secure, reliable, and performant experiences for our customers.

We’re here to help if you need it. If you have questions, please let us know in Stack Overflow with the [MicrosoftGraph] tag.

Thank you in advance for updating and opening your apps to a wider range of useful and intelligent features on Microsoft Graph. We are extremely excited about the growing opportunities that Microsoft Graph offers to developers, and we remain  fully committed to continue our journey to empower developers to access Office 365 data with the most modern features and tools.


Happy coding!

Yina Arenas

Microsoft Graph Program Manager




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