Office 365 Planned Service Changes for 2020

The goal of this post is to compile all publicly announced Office 365 service changes for 2020, especially those that may require admin action, into a single reference. These changes are listed below in chronological order, based on the "Action Required" or "Effective" date. Additional information and resources related to these changes are provided where applicable. Updates will be made to this post as new service changes are announced, or updates to announced changes are provided.

Note: All changes may not have been communicated to your tenant / environment.


Update Log:


  • Added Retirement of Unified Messaging in Exchange Online - effective February 2020



  • Updated Office 365 system requirements changes for Office client connectivity - added "What will happen on October 13, 2020?" details
  • Added Changes to Exchange Web Services API for Office 365 - action required by October 13, 2020


  • Updated Focused Inbox and retirement of Clutter - corrected year in Action Required date from 2018 to 2020
  • Added Changes to Office 365 ProPlus system requirements - action required by January 14, 2020


  • Added Focused Inbox and retirement of Clutter - January 31, 2020


  • Updated Office 365 system requirements changes for Office client connectivity - added "Office 365 system requirements changes effective 2020" image from Ignite 2017 session


  • Added Office 365 system requirements changes for Office client connectivity


Focused Inbox and retirement of Clutter

Status: Active

Action Required by: January 31, 2020

Details: In July 2016 we announced that Focused Inbox, a new feature in Outlook that helps you cut through the noise of email to focus on what matters most, would be coming to Office 365 customers. Focused Inbox first rolled out to customers who use modern authentication, and earlier this month we added support for basic authentication. This means that Focused Inbox is now available to all Office 365 customers on the Monthly Channel of Office 365 ProPlus. If you aren’t seeing it yet, be sure your Outlook version is updated to build 16.0.8730 Version 1711 or greater. Focused Inbox will be available to customers on the Semi-Annual Channel in the March 2018 Semi-Annual Targeted release, and the July 2018 Semi-Annual release, according to that channel’s standard schedule.

With Focused Inbox now rolled out, we’d like to share more about our plans for Clutter. As we mentioned in July, Focused Inbox is the long-term replacement for Clutter. It carries forward Clutter’s capabilities but removes the need to visit a separate folder to check your less-actionable messages. Because Clutter and Focused Inbox use the same algorithms for sorting messages, there are no changes to how email is classified, just a better user experience.

We’ll continue to make Clutter available to Office 365 customers until January 31, 2020. To prepare for Clutter’s eventual retirement, we’ve turned the feature off by default for new users. It’s also deactivated for those with extremely low usage (less than 12 emails per month being moved to the Clutter folder), however they can re-enable Clutter at any time, if desired.

Additional Information: Update on Focused Inbox and our plans for Clutter


Retirement of Unified Messaging in Exchange Online

Status: Active

Effective: February 2020

Details: Microsoft is retiring Unified Messaging (UM) in Exchange Online and replacing it with Cloud Voicemail and Auto Attendant services. This impacts voicemail processing and Auto Attendant in Exchange Online for all customers using these workloads. The following servers connecting to Exchange UM Online will be transitioned by Microsoft to Cloud Voicemail on or before February 2020:

  • Lync Server 2013
  • Skype for Business Server 2015

Please note this announcement refers to Unified Messaging which is the processing of voicemails and Auto Attendant in Exchange Online. Storage of voicemails will continue to be supported in Exchange Online and Exchange on-premises Servers.

Customers using the above-mentioned servers to connect to Exchange UM Online will be transitioned to Cloud Voicemail by Microsoft. The transition timing will vary depending upon how your company has utilized the UM features. Over the course of this calendar year, we will selectively notify customers via the Office 365 Message Center of their coming transition. The first group of customers will be notified in February 2019 and then can expect to be transitioned in March 2019. The experience for each customer will be transparent – Microsoft will switch your users over to Cloud Voicemail and perform the necessary validation and testing.

Customers who have received a transition notification and would like to request postponement can do so by submitting a request via the support tool in the Office 365 Admin Portal. Please remember that final retirement date is February 2020.

Lync 2010 Servers connected to Exchange Online Unified Messaging will not be transitioned or supported with Cloud Voicemail. Customers using this topology must upgrade to Skype for Business Server prior to February 2020 for continued voicemail support via Cloud Voicemail.

Additional Information:


Changes to Exchange Web Services for Office 365

Status: Active

Action Required by: October 13, 2020

Details: Over the last few years, we have been investing in services to help developers access information in Office 365 in a simple and intuitive way. As we make progress on this journey, we have continued to evaluate the role of Exchange Web Services (EWS) and how to best interact with Office 365 data and authenticate with Exchange Online. We are making the following announcements:

  • Basic Authentication for Exchange Web Services (EWS) will be retired, beginning October 13, 2020, as we focus our efforts on OAuth 2.0.
  • We are investing our development resources in Microsoft Graph as the future mechanism for accessing Exchange Online data.

With this change, we are focusing our investments in OAuth 2.0 for authentication and authorization as the preferred method to access Exchange Online. Starting October 13, 2020, we will completely remove Basic Authentication for EWS as a way to access Exchange Online. Additionally, EWS will continue to receive security updates and certain performance updates, but product design and features will remain unchanged.

If you have been using Basic Authentication for EWS in your applications, you should plan to use OAuth 2.0 for authentication and authorization, before October 13, 2020. In addition, we strongly suggest that you plan on transitioning to Microsoft Graph based Outlook APIs to continue accessing Exchange Online data.

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