Microsoft has deployed its first major security update of 2026 for Windows 11, addressing a persistent power management flaw that has been draining laptop batteries by preventing certain NPUs from entering low-power states during idle periods. The update, released as part of January's Patch Tuesday, also removes four legacy modem drivers and introduces safeguards to stabilize future Secure Boot certificate updates.
At the core of this month's release is a fix for a long-standing issue where third-party Neural Processing Units (NPUs) failed to power down efficiently when systems were idle. While NPUs are designed to consume minimal energy, improper power management has led to noticeable battery drain on affected laptops and hybrid devices. The update corrects this behavior, ensuring better power efficiency without requiring hardware changes.
In addition to the NPU fix, Microsoft is removing support for four legacy modem drivers: agrsm64.sys, agrsm.sys, smserl64.sys, and smserial.sys. This move effectively ends compatibility with devices relying on these components, as they will no longer be included in future Windows updates.
To prevent potential disruptions during Secure Boot updates, Microsoft is implementing a measured rollout approach. Updates to the Secure Boot certificate infrastructure will now be deployed only after devices demonstrate stable update histories, reducing the risk of widespread failures. This cautious approach aims to balance security improvements with system stability.
The update also includes several technical fixes across other components
- Windows Subsystem for Linux (WSL) now resolves networking issues that caused 'No route to host' errors when accessing corporate VPN resources, a problem introduced in a previous update.
- Azure Virtual Desktop environments receive a patch for RemoteApp connection problems linked to an earlier security update.
- Windows Deployment Services disables hands-free deployment by default, requiring manual reactivation—a change intended to improve control over automated processes.
- A core system component, WinSqlite3.dll, has been updated to address detection conflicts with security scanning tools, though no new user-facing features are included in this release.
While the update focuses primarily on behind-the-scenes improvements and fixes, its impact on battery life for NPU-equipped devices could be significant for users relying on long-term portability. The removal of legacy modem drivers may also prompt some hardware manufacturers to reconsider their compatibility strategies moving forward.
The January 2026 update is now available as an optional download through Windows Update, with automatic installation expected in the coming days depending on system configuration. Users who rely on the removed modem drivers should verify hardware compatibility or seek alternative solutions promptly.
