Applies To
Windows 11 version 26H1, all editions

This article applies to Copilot+ PCs only.

Introduction

Phi Silica is a Windows AI component for Qualcomm‑powered Copilot+ PCs that enables on‑device language intelligence across Windows features and applications. It is a Microsoft‑developed, Transformer‑based small language model (SLM) optimized for machine‑learning inference on the device’s Neural Processing Unit (NPU), allowing language tasks to be executed entirely on the device rather than in the cloud. This on‑device execution delivers fast, low‑latency responses while keeping user data local to support privacy‑focused workflows. Despite its compact footprint, Phi Silica provides core language model capabilities such as text understanding, summarization, rewriting, and short‑form content generation within the power and performance constraints of Copilot+ hardware. The Phi Silica AI component supports a broad range of Windows and Copilot+ experiences—including productivity, accessibility, and AI‑assisted workflows—and is exposed to developers through Windows AI APIs, enabling applications to integrate local, machine‑learning–based language processing without requiring cloud connectivity.

Summary

This Phi Silica update includes improvements to the Phi Silica AI component for Windows 11, version 26H1.

How to get this update

Windows Update

This update will be downloaded and installed automatically from Windows Update.

Prerequisites

You must have the latest cumulative update for Windows 11, version 26H1 installed.

Replacement information

This update replaces the previously released update KB5083513.

Check update history

To determine whether this update is present on the device, go to Settings > Windows Update > Update history.

After this update is installed, you should find the following update listed in Update history depending on the processor type in the device:

  • 2026-04 Phi Silica version 1.2603.373.0 for Qualcomm-powered systems (KB5089866)

References

For a list of AI updates on supported devices, see the following resources:

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