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Microsoft Teams: External domains anomalies report

Microsoft 365 Message Center Archive by Merill Fernando · Microsoft may not have sent this notice to your tenant.
Microsoft Teams
Microsoft 365 admin center

Rollout

Roadmap
536572

Rollout dates are often only in the text. When Microsoft moves them, the change shows under "What changed".

Schedule dates changed in the text

Date phrases in schedule sentences differ between the versions this installation saw
  • Seen 27 Mar 2026 early April 2026, mid-April 2026 → mid-May 2026, late May 2026
  • Seen 27 Feb 2026 early March 2026, mid-March 2026 → early April 2026, mid-April 2026
  • Seen 29 Jan 2026 late February 2026, March 2026 → early March 2026, mid-March 2026

Read from date phrases in Microsoft's text, not from notice metadata. A changed phrase can be a moved rollout, a new milestone or just rewording; "What changed" below shows which.

What the notice says

Microsoft’s text, with source markup removed
Updated March 27, 2026: We have updated the timeline. Thank you for your patience.  Introduction To help admins detect unusual or potentially risky interactions with external organizations, Microsoft Teams is introducing the External domains anomalies report. This report analyzes cross-tenant communication patterns for your tenant and highlights sudden spikes or abnormal engagement activity. These insights support proactive investigation and help protect your organization while enabling secure external collaboration. This message is associated with Microsoft 365 Roadmap ID 536572. When this will happen General Availability (Worldwide): Rolling out in mid-May 2026 (previously early April) and expected to complete by late May 2026 (previously mid-April). How this affects your organization Who is affected: Teams administrators can view this report for their Microsoft 365 tenant if their organization collaborates with external organizations. What will happen: A new External domains anomalies report will be available in the Microsoft Teams admin center under Protection reports. Admins can select Communication anomalies, choose a date range, and run the report to view results: Insights include external domains with unusual communication activity:External domain name Total anomalies detected New 1:1 threads created by that domain New group threads created by that domain A Block option is available directly in the report for managing external domains: What you can do to prepare No action is required to access the report. To receive proactive alerts: Enable External domains anomalies alerts in the Teams admin center:Go to Notifications & alerts > Rules. Select External domains anomalies. Set status to Active. Specify a Teams channel for notifications if desired. Daily alerts will summarize the top five domains with unusual activity. Compliance considerations No compliance considerations identified. Review as appropriate for your organization.

What changed

Between archive captures, newest first

  1. Updated FebruaryMarch 27, 2026: We have updated the timeline. Thank you for your patience. … ID 536572. When this will happen General Availability (Worldwide): Rolling out in early April mid-May 2026 (previously early March)April) and expected to complete in mid-Aprilby late May 2026 (previously mid-March). mid-April). How this affects your organization Who is affected: Teams administrators can view …

  2. Updated January 29,February 27, 2026: We have updated the timeline. Thank you for your patience.  Introduction … 536572. When this will happen General Availability (Worldwide): Rolling out in early MarchApril 2026 (previously late February)  early March) and expected to complete in mid-March 2026.mid-April 2026 (previously mid-March). How this affects your organization Who is affected: Teams administrators can view …

  3. Updated January 29, 2026: We have updated the content.timeline. Thank you for your patience.  Introduction To help admins detect unusual or … ID 536572. When this will happen General Availability (Worldwide): Rolling out in early March 2026 (previously late February 2026 February) and expected to complete in March mid-March 2026. How this affects your organization Who is affected: Teams administrators can …

    • Tags New feature, User impact, Admin impact → Updated message, New feature, User impact, Admin impact

    Updated January 29, 2026: We have updated the content. Thank you for your patience.  Introduction To help admins detect unusual or potentially risky interactions with external … domains with unusual communication activity:External domain name Total anomalies detected New 1:1 chat threads created by that domain New group chat threads created by that domain A Block option is available directly in …

  5. · first version seen

Linked documentation

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No related evidence found in this installation's recent collection. This does not establish that no announcement exists.

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  • Whether your tenant is affected: this is Microsoft's notice, not a check of your settings.
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