Windows 11 Release Preview: Copilot in Excel and critical security patches now live

Microsoft pushed three new Windows 11 Release Preview builds today, May 14, giving Insiders an early look at what is likely to ship to all users in the coming months. The updates cover Windows 11 versions 24H2 and 25H2 via KB5089573, pushing both to Build 26100.8514 and 26200.8514, respectively, alongside a separate build for the upcoming Windows 11 version 26H1 via KB5089570, which targets next-generation AI PCs with strict hardware requirements.

Release Preview builds are typically the final code before a feature update ships to all users. Microsoft sources indicate that 24H2 and 25H2 could reach general availability as early as June 2026, while 26H1 is on track for a late-third-quarter launch timed to the back-to-school PC refresh cycle. The 26H1 build has specific hardware requirements: devices must have an NPU capable of at least 40 TOPS, 16 GB of RAM, and a minimum of 256 GB of NVMe storage.

Security fixes and what is new

The release preview builds integrate fixes for two zero-day vulnerabilities from the May 2026 Patch Tuesday: CVE-2026-1127, a kernel elevation of privilege flaw, and CVE-2026-1139, a remote code execution vulnerability in the Windows graphics component. Both are fully baked into the cumulative update and will be part of the final public release.

KB5089573 also introduces Shared LE Audio, enabling a single audio stream to be broadcast to multiple Bluetooth devices simultaneously. Multi-app camera support arrives as well, allowing two applications to access the same camera input at the same time, a change that addresses a longstanding limitation for users running video calls and recording software in parallel. NPU task management improvements are included across all three builds, helping Windows better distribute AI workloads between the CPU and the neural processing unit on Copilot+ devices.

Copilot in Excel is now live in all three Release Preview builds, letting users generate formulas, pivot tables, and data visualisations by typing natural language questions directly into a taskbar pane while working in a spreadsheet. The feature requires a Microsoft 365 subscription but runs on locally cached language models, so it works without an internet connection. The Windows AI Studio toolkit, previously limited to the Dev channel, also ships with these builds, providing developers with pre-trained models for image classification, sentiment analysis, and text summarisation that run exclusively on the NPU.

Enterprise and IT admin controls

All three builds introduce new Group Policy Objects that give IT administrators direct control over AI features. Admins can disable or restrict Copilot integrations, manage which applications can access the NPU, and set policies for how AI agents interact with the taskbar. Microsoft describes these GPOs as part of a broader effort to make AI features enterprise-ready before the builds go to general availability. Insiders enrolled in the Release Preview channel can pull today's updates through Windows Update immediately. A known issue affects VPN software on some configurations, with connections failing to re-establish automatically after waking from sleep, requiring a manual toggle.

Notebookcheck covered the May 2026 Patch Tuesday launch.