KB5087539: [Daylight saving time (DST)] This update supports the 2023 DST change for the Arab Republic of Egypt.
Windows Server 2025Microsoft
May 12, 2026—KB5087539(OS Build 26100.32860)
Improvements
This security update contains fixes and quality improvements from KB5082063 (released April 14, 2026) and KB5091157 (release April 19, 2026). The following summary outlines key issues addressed by this update. Also, included are available new features. The bold text within the brackets indicates the item or area of the change.
- [Secure Boot] With this update, Windows quality updates include additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. Devices receive the new certificates only after demonstrating sufficient successful update signals, maintaining a controlled and phased rollout.
- [Connectivity] This update improves the reliability of Simple Service Discovery Protocol (SSDP) notifications to help prevent the service from becoming unresponsive.
- [Daylight saving time (DST)] This update supports the 2023 DST change for the Arab Republic of Egypt.
- [Domain controllers] This update improves the performance of the Local Security Authority Subsystem Service (LSASS) on domain controllers when Microsoft Defender is enabled. It reduces CPU and memory usage during Event Tracing for Windows collection of IDL_DRSGetNCChanges events.
- [Remote Desktop (known issue)] Fixed: This update addresses an issue that affects the Remote Desktop Connection security warning dialog. The dialog could render incorrectly in multi-monitor scenario when the monitors had different scaling set. This might occur after installing the April 2026 (KB5082063) security update. For more information, see Understanding security warnings when opening Remote Desktop (RDP) files.
- [Sign-In] After you install the Windows update released on or after March 10, 2026, some users might experience an issue signing in to apps with a Microsoft account. Even when the device has a working Internet connection, a “no Internet” error appears during sign in and prevents access to Microsoft services and apps such as Microsoft Teams
