Microsoft's first Patch Tuesday of 2026 delivers update KB5074109 to Windows 11 versions 24H2 and 25H2, focusing on power optimization and security infrastructure. The release finally corrects a Neural Processing Unit issue where certain third-party NPUs failed to enter low-power states during system idle, directly impacting battery performance on affected laptops and hybrid devices. Usually NPUs are low power consumers, but improper power loading is still draining precious battery life. Microsoft is also introducing a measured rollout mechanism for Secure Boot certificate updates, targeting devices only after they demonstrate stable update histories to prevent widespread deployment failures.

Additionally, Microsoft announced a complete removal of four legacy modem drivers: agrsm64.sys, agrsm.sys, smserl64.sys, and smserial.sys, which terminates support for hardware dependent on these components. The Windows Subsystem for Linux receives a fix for mirrored networking failures that generated "No route to host" errors when accessing corporate VPN resources, a regression introduced in KB5067036. Azure Virtual Desktop environments receive a patch for RemoteApp connection issues caused by KB5070311. Windows Deployment Services now disables hands-free deployment by default, requiring manual reactivation. The core component WinSqlite3.dll has been updated to address detection issues with security scanning tools, although there are no new user-facing features in this month's security update.