Microsoft Edge 157 Stable: XSLT Deprecation Timeline, OneAuth Sign-In and Copilot Changes

The release also adds Apple-account sign-in, removes tab fading, changes tab hover cards and adds four enterprise policies. Some of these changes need action from admins and some need a heads-up to the helpdesk.

The quick version​

Microsoft's Stable release notes show these channel versions:

Before Stable, the build went through Beta. Microsoft's Beta notes list Version 157.0.4341.36: November 2, 2026 as the last Beta build before this release. Neowin lists the offline installers at 205.0 MB for 64-bit, 183.0 MB for 32-bit and 188.0 MB for ARM64.

Microsoft also notes that Stable updates roll out progressively over one or more days. If Edge doesn't offer 157 yet, it probably will soon.

Section summary: Edge 157 is a full Stable release. Extended Stable customers stay on version 156 for now and received a bug-fix update on the same day.

XSLT: a long countdown with a firm end date​

This is the change most likely to cause problems in enterprise environments. Microsoft Edge will disable the XSLTProcessor JavaScript API and XML processing instructions that reference XSLT stylesheets by default. XML processing instructions that reference CSS stylesheets are not affected.

The schedule is staggered by channel:

• Microsoft Edge 157: Browser-native XSLT will be off by default in the Canary, Dev, and Beta channels.
• Microsoft Edge 159: Browser-native XSLT will be off by default in the Stable channel.
• Edge 176 is the end date for the temporary workarounds.

Version 157 does not remove XSLT on Stable today. The preview channels lose it now, which gives organizations a test bed before Stable follows in 159.

There are two temporary ways to keep XSLT working. The existing XSLTEnabled policy can explicitly enable or disable XSLT regardless of the browser default. For public sites, site owners can temporarily use the XSLT deprecation origin trial to keep browser-native XSLT enabled for a registered origin. Microsoft's Stable notes say both mitigations are planned to stop working in Edge 176. Microsoft 365 tenant admins can find more detail in Message Center item MC1509789.

Who should worry?​

Client-side XSLT is rare on the consumer web. It is more common in older line-of-business software, such as:

• intranet reporting portals
• XML-based document viewers
• systems that send raw XML to the browser and let a stylesheet turn it into HTML

These systems have often worked untouched for 15 years. In my experience, nobody knows they exist until a rendering error turns up in a helpdesk queue.

An XSLT readiness checklist​

Microsoft's recommended administrator actions come down to these steps:

1. Inventory internal and business-critical apps that use XSLTProcessor or XML processing instructions that reference XSLT stylesheets.
2. Test those apps with browser-native XSLT turned off. Edge 157 on Beta or Dev already has it off by default, so a pilot ring on a preview channel is the simplest way to do this.
3. Migrate the transformations to server-side processing, a JavaScript-based transformer or another supported implementation.
4. Update internal development guidance, support documentation and test plans.
5. Communicate the change to application owners, helpdesk staff and affected users.
6. Fall back on the XSLTEnabled policy only if the migration misses the Edge 159 deadline. Microsoft also mentions third-party polyfills and browser extensions as options.

Treat the policy as temporary. It buys time, and it stops working in Edge 176.

Section summary: Nothing breaks on Stable in version 157, but the preview channels lose XSLT now and Stable follows in 159. Find and test affected apps before then.

Sign-in: the legacy WAM path is retired​

Edge retired the legacy direct-WAM sign-in implementation in favor of OneAuth, completing the transition with Edge 157. Some users may need to sign in again.

The name invites a misreading, so here is the important caveat: OneAuth continues to use Windows Web Account Manager (WAM) internally; WAM itself is not being deprecated. Edge still uses Windows' account broker. It no longer calls WAM directly and goes through Microsoft's OneAuth library instead.

According to Microsoft, the vast majority of users have already transitioned automatically with no interruption. For remaining profiles that have not yet migrated, the transition will complete upon updating to version 157. In rare cases, some users may need to sign in to Microsoft Edge again.

When Neowin covered the change in advance, it reported that unmigrated profiles and organizations that had specifically disabled OneAuth WAM are the ones affected. It also noted that admins should also let support teams know that a small number of users could see a sign-in action on their profile menu after updating to Edge 157.

How to check a profile​

1. Open edge://signin-internals in the profile you want to check.
2. Find Edge Auth Library Information → Library.
3. Neowin explains that if OneAuth is displayed, the profile is already using the modern path and no action is required. If it still shows WAM, that profile has not migrated yet.

For organizations that want to force-test the new path, Microsoft documents a launch flag: msedge.exe --enable-features=msForceOneAuthWAM. Close all Microsoft Edge processes, including background processes, because the flag does not take effect if Microsoft Edge is already running.

Startup Boost and background apps can keep Edge running after you close its windows. Check Task Manager for leftover msedge.exe processes before deciding that the flag doesn't work.

Section summary: Most users won't notice the change. A few profiles may ask the user to sign in again, and helpdesks should know why.

Faster launches on newer Windows 11 builds​

Microsoft's Stable notes describe Accelerated App Launch as a change to how Windows starts Edge when the browser is already running in the background. Microsoft says this reduces delays when you open a link or start Edge from the taskbar or Start menu. It says the biggest gains come when the PC is busy or under load.

The feature requires:

• Windows 11 version 25H2, 26H1 or 26H2
• Edge version 150 or later

Windows 10 and older Windows 11 releases are not on the list. Microsoft has not published benchmark numbers in these notes, so wait for your own testing before expecting a specific speedup.

Copilot, Apple accounts and tab changes​

Copilot updates​

Neowin says Edge 157 upgraded the Copilot new tab page with a unified search and chat box, suggested actions, and curated work content. It also updated the Copilot side pane with a simplified interface, refreshed icons, and features such as Copilot Voice and Vision.

Microsoft's notes add a reassurance for enterprises: security, compliance, privacy and enterprise controls are unchanged. Microsoft also asks admins to add *.cloud.microsoft to allow lists ahead of a planned Copilot URL redirect. The relevant Message Center item is MC1462915.

If your web filter only allows the older Copilot domains, Microsoft 365 Copilot Chat in Edge may stop working when that redirect arrives. Update the allow list first.

Apple account sign-in​

Edge now added the ability to sign in to Edge using an Apple account, alongside Microsoft account sign-in. Microsoft's notes say users can do this from the profile menu and the Edge sign-in screen.

Admins can control the option with the NonMicrosoftAccountSignInEnabled policy. Organizations that don't want work devices syncing to personal Apple accounts should review that policy now.

Tab changes​

• Fade inactive tabs is gone. The setting no longer appears under edge://settings/system/managePerformance, and inactive tabs no longer fade.
• Tab hover cards show more memory detail. Microsoft says they now give clearer information about each tab's memory use and the memory saved when inactive tabs are discarded. Tab preview images and memory information now have separate settings.

Starting Edge with Windows on managed devices​

Edge 157 adds an opt-in experience that lets users on managed devices choose whether Edge starts automatically with Windows. Admins can manage this with the LaunchEdgeOnWindowsStartupEnabled policy, which supports opt-in, opt-out and user-choice configurations.

Microsoft calls this a controlled feature rollout, so not every device will see it right away. The same item appeared in the Edge 156 notes, which suggests the rollout is still in progress.

Section summary: The visible changes are a larger Copilot presence, a new sign-in option and some tab tidying. The policies listed above let admins control most of them.

Policy changes and a freeze fix​

Edge 157 adds four enterprise policies:

Edge 157 also deprecated the BackForwardCacheForWebSocketsAllowed policy. If your baseline configures it, plan to remove it.

Microsoft also addressed the RoamingProfileSupportEnabled policy. Chromium has deprecated it, but Microsoft says Edge will not follow Chromium's timeline. Microsoft promises 60 days' notice in the Microsoft 365 Message Center and the policy documentation before it deprecates the policy in Edge. That matters for VDI and roaming-profile environments.

The only fix listed in the release fixed a prolonged browser freeze affecting some users interacting with specific web applications while accessibility features were enabled. Microsoft does not name the affected applications or explain the cause. If screen-reader users in your organization reported hangs, test them on 157, but don't assume this fix covers every accessibility-related freeze.

For developers: the Edge 157 web platform​

Microsoft's Edge 157 web platform release notes, also dated November 5, add several capabilities inherited from Chromium:

• CSS:
  • a corner shorthand that combines border-radius and corner-shape
  • text-decoration-inset
  • custom strings for text-overflow, such as " (more)" in place of an ellipsis
  • new position-visibility values anchor-valid and anchor-visible; anchors-visible is now a deprecated alias
• HTML: <camera>, <microphone> and <geolocation> support displaymode="icon-only".
• Web APIs:
  • new HTML insertion and streaming methods that effectively replace insertAdjacentHTML(), such as appendHTML() and streamHTML()
  • a Sanitizer API javascriptURLs option
  • HTML-in-canvas
  • style and layout durations in the Long Animation Frames API
  • CORS enforcement for Background Fetch
  • ProgressEvent in service workers
  • Web Bluetooth's BluetoothRemoteGATTServer becoming an EventTarget
  • the WebGPU atomic-vec2u-min-max feature

The CORS enforcement for Background Fetch is a security change as well as a feature. Microsoft says it stops sites from using Background Fetch to get around CORS and related checks such as Local Network Access. Any app that relied on the old behavior will now hit CORS errors.

The bottom line​

Most users will get Edge 157 automatically and mainly notice the Copilot changes. Administrators have more to do:

1. Before Edge 159: find and test apps that depend on XSLT.
2. Now: check edge://signin-internals on managed profiles and tell the helpdesk that some users may need to sign in again.
3. Now: add *.cloud.microsoft to Copilot allow lists.
4. Now: review NonMicrosoftAccountSignInEnabled and LaunchEdgeOnWindowsStartupEnabled against your policy baseline.

The XSLT deadline is the most urgent item. Edge 159 is the next Stable milestone, and Microsoft's own schedule gives organizations only a short window to find and migrate affected apps.