M365 Message Center

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22.04.2026

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Windows

Microsoft is hosting two upcoming Ask Microsoft Anything (AMA) events focused on updating Secure Boot certificate updates across your Windows estate before certificate expirations begin in June 2026. These AMAs are designed to help you get clarity on what’s changing and how to plan for deployment across your environment. Bring your questions and get practical guidance directly from Microsoft experts. When will this happen: Secure Boot certificates on Windows devices begin expiring in June 2026. The upcoming AMAs will take place on April 23, 2026 and May 18, 2026. What you need to do to prepare:Review the Secure Boot playbook to understand requirements, affected scenarios, and available tooling, then add one or both upcoming AMAs to your calendar:Secure Boot AMA – April 23, 2026, 8:00 AM PDT Secure Boot AMA – May 18, 2026, 8:00 AM PDT Post your questions in the comments section of each pa

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22.04.2026

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Windows

IMPORTANT: This notice is only relevant for environments where:ASP.NET Core is used Scan Cab is used to check for update compliance The April 2026 Scan Cab was deployed before 10:00 PM PT on April 21, 2026 An updated version of the April 2026 Scan Cab was made available at 10:00 PM PT on April 21, 2026. This Scan Cab includes new metadata corresponding to updates for ASP.NET Core. The Microsoft update for ASP.NET Core released on April 21, 2026, includes additional protections to address CVE-2026-40372: ASP.NET Core Elevation of Privilege Vulnerability. See the Additional information section of this message for details. How this affects your organization:IT administrators who downloaded the Scan Cab before 10:00 PM PT on April 21, 2026, should re-acquire and re-deploy it if the Scan Cab is used to assess updates for environments where ASP.NET Core is used. No action is required for envir

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19.04.2026

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Windows

Microsoft has released out-of-band (OOB) updates today, April 19, 2026, to address issues introduced by the April 2026 Windows security update. A limited number of Windows Server 2025 devices might experience failures installing the April 2026 security update (KB5082063). In addition, some versions of Windows Server may experience domain controllers restarting repeatedly after installing the April 2026 security update. To address these issues, Microsoft has released OOB updates for the Windows Server versions listed below. Note: The Windows Server 2025 OOB update (KB5091157) addresses both the installation failure issue and the domain controller restart issue. OOB updates released for other supported Windows Server versions address only the domain controller restart issue. For complete guidance and installation instructions, see the relevant KB articles: Standard Windows updatesWindows S

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17.04.2026

Services

Windows

For Windows devices in Egypt, a workaround is available for an issue affecting Daylight Saving Time (DST). Between April 24 and April 30, 2026, calendar events and meeting times in Egypt will appear off by one hour only for Windows Server 2016. This is due to a calendar edge case: a five-week April in 2026. Clocks will be correctly set to Egypt DST time zone on May 1, 2026, without any further intervention. If needed, a temporary workaround is available for the affected week. When will this happen:The workaround is available today. April 24-30, 2026: Affected devices might see calendar events off by an hour. May 1, 2026: Clocks will be correctly set to Egypt DST time zone without any further intervention, whether you use the workaround or not. How this will affect your organization:If your organization has devices affected by this issue and you don’t apply the workaround, the impact is a

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16.04.2026

Services

Microsoft 365 apps · Microsoft Copilot (Microsoft 365) · Microsoft 365 Copilot Chat

[Introduction] We’re updating how users access Copilot in Excel to provide a clearer, more consistent, and more intuitive experience across Microsoft 365 apps. These changes consolidate multiple Copilot entry points into a single, predictable location and establish Excel Edit Mode in the right-side chat pane as the primary Copilot interface. This update improves discoverability, simplifies user workflows, and aligns the Excel Copilot experience with other Microsoft 365 applications. [When this will happen:] General Availability (Worldwide): Rollout begins in late April 2026 and is expected to complete by early June 2026. General Availability (GCC, GCC High, and DoD): Rollout begins in early October 2026 and is expected to complete by late October 2026. [How this affects your organization:] Who is affected: All users of Microsoft 365 apps for Excel on Windows, macOS, and the web with Copi

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16.04.2026

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Microsoft Entra

Introduction Beginning January 30, 2026, Microsoft Entra ID Governance will require all tenants to have a linked Azure subscription to continue using Identity Governance features for guest users. This change ensures accurate billing for governance actions performed by guests and supports continued access to advanced governance capabilities. When this will happen: General availability and enforcement begin on January 30, 2026. How this will affect your organization: Who is affected: Organizations using Microsoft Entra ID Governance features for guest users (userType = Guest). Admins managing lifecycle workflows or Entra ID Governance features in entitlement management for external or guest identities. Access reviews will be included by March 31, 2026. What will happen: If your tenant does not have a linked Azure subscription, creation or updates of policies scoped to guest users using pre