kb5089570

KB5089570 is an optional preview cumulative update released by Microsoft on May 26, 2026, for Windows 11 version 26H1, bringing the OS build to 28000.2179. This update includes non-security fixes, File Explorer improvements, Xbox mode enhancements, Secure Boot servicing updates, and AI component updates for Copilot+ PCs. It also introduces enterprise management improvements and servicing-stack changes. While not a Patch Tuesday security release, KB5089570 provides administrators with a preview of upcoming features and platform hardening. The update reflects Microsoft's strategy of using optional previews to test a mix of shell polish, hardware-era features, and security infrastructure before broader rollout.