Microsoft Edge Is Removing XSLT Support Starting December 2026

Microsoft will disable native XSLT support in Edge starting with version 159, expected in mid-December 2026, before removing the technology completely in 2027.

According to Microsoft 365 Message Center MC1509789, the change could affect organizations that rely on websites and internal applications using XSLT to transform XML documents.

XSLT, introduced in 1999, allows websites to transform XML documents into formats such as HTML. Microsoft is retiring the technology because of security concerns, declining usage, and the availability of modern alternatives.

What changes in Microsoft Edge 159?

Starting with Edge 159, Microsoft will disable the XSLTProcessor JavaScript API and XML processing instructions that reference XSLT stylesheets by default.

As a result, websites and internal applications that depend on browser-native XSLT may stop working correctly. However, XML processing instructions that reference CSS stylesheets will continue to function.

Microsoft recommends that organizations use Edge’s Lighthouse tool to identify websites that rely on XSLT. Administrators should also review affected applications, migrate to modern alternatives, or contact software vendors for updates.

Microsoft offers a temporary workaround until 2027

Organizations that still need XSLT can temporarily restore support by setting the XSLTEnabled policy to true.

However, this workaround will not remain available indefinitely. Microsoft plans to remove the policy entirely with Edge 176 in summer 2027, permanently ending browser-native XSLT support.

The change adds to other compatibility concerns for enterprise customers. Microsoft recently warned that Chromium changes could break RD Web Access in Edge and Chrome.

Organizations that depend on XSLT should identify affected applications before Edge 159 arrives and complete their migrations ahead of the final removal in 2027.

In other news, Microsoft Edge could soon update without requiring users to restart the browser.

Via Neowin