Skype for Business EWS retirement preparation

1. August 2026 Published timing is qualified; effectiveness is not confirmed.
2. 1 Oct 2026 Published timing is qualified; effectiveness is not confirmed.
3. October 2026 Published timing is qualified; effectiveness is not confirmed.
4. Retired / removedafter 1 Apr 2027 Published timing is qualified; effectiveness is not confirmed.

1. August 2026 7 weeks agomonth windowend ofthe end of
   • Key dates and timelineRequirement
   • : Deadlinein What administrators must doRequirement
   • Action 1: Configure the EWS allow list (before end of August 2026)Milestone
   • Configuration stepsScope1 condition
   • Recommended next stepsRecommendation
2. September 2026 3 weeks agomonth windowbefore
   • Configuration stepsRecommendation
3. 1 Oct 2026 2 weeks ago
   • $nullin How EwsEnabled worksMilestone
   • Configuration stepsScope1 condition
4. October 2026 this window includes todaymonth windowstarting
   • $truein How EwsEnabled worksMilestoneException1 condition
5. Today · 21 Oct 2026
6. 1 Apr 2027 in 5 monthsafterbeforeRetired / removed · unconfirmed
   • GuidanceMilestoneScope

     Microsoft is retiring Exchange Web Services (EWS) in Exchange Online, with full retirement on April 1, 2027. EWS is…

   • Key dates and timelineMilestone
   • Full EWS retirement, no exceptionsin Key dates and timelineMilestone
   • : Deadlinein What administrators must doRequirement
   • Action 2: Install the upcoming Skype for Business Server update (before April 1, 2027)MilestoneException1 condition
   • Recommended next stepsMilestoneRecommendation

Settings and overrides named on this page

Registry values, policies and cmdlets the source mentions, with the dated steps that name them. Read the source for the values to set.

• Get-CsOAuthConfiguration

Requirements, exceptions and scope

• GuidanceRequirementScope1 condition2 passages

  APPLIES TO: 2015 2019 Subscription Edition…

• Who is affectedException2 conditions2 passages
• Skype for Business and Exchange integration impactException1 condition1 passage
• What administrators must doRequirement3 passages
• How EwsEnabled worksException1 condition1 passage
• Configuration stepsRequirementScope1 condition3 passages
• Recommended next stepsRecommendation3 passages
  Get-CsOAuthConfiguration
• Related articlesScope1 passage

Extracted automatically from Microsoft's wording. Confirm dates, conditions and whether they apply to you in the source before acting; a month or quarter is a window, not a day.