Google is removing the final technical workaround that let some Chrome users keep running classic ad blockers like uBlock Origin, more than a year after the company began phasing the extension out under its Manifest V3 transition. Chrome 150, scheduled to reach the stable channel on June 30, 2026, deletes the last override flag from Chromium's code entirely, closing a door that power users and IT departments had been propping open since late 2024.

What's Actually Changing

The change centers on a flag called ExtensionManifestV2Disabled, a residual switch buried in Chrome's code that allowed technically inclined users to re-enable Manifest V2 extensions after Google had otherwise turned them off. A Google engineer confirmed the removal directly in a Chromium code review, stating plainly that MV2 extensions are no longer allowed in any supported version of Chrome and that support for them is being removed entirely.

A second flag, ExtensionManifestV2Unsupported, has also allowed a more fragile method: disabling it and then manually dismissing a warning banner on the extensions page to bring MV2 tools back. Chrome 151, expected roughly four weeks after Chrome 150, removes that flag too, along with ExtensionManifestV2Availability and AllowLegacyMV2Extensions. Once both releases land, there is no supported workaround, no enterprise policy override, and no hidden setting left to restore full Manifest V2 functionality.

Timeline of the phase-out: Chrome 138 (July 2025) disabled MV2 for all standard users and removed the in-browser toggle. Chrome 139 eliminated the enterprise override policy. Chrome 149 was the last version where command-line flags reliably worked. Chrome 150 (June 30, 2026) removes the primary remaining override. Chrome 151 (expected July 2026) closes the last DevTools-based method.

Why This Matters for uBlock Origin Users

uBlock Origin's classic version relies on the webRequest API to inspect and block network requests dynamically before they load, a capability Manifest V3 restricts in favor of a more limited, declarative system called declarativeNetRequest. That limitation is why the original extension cannot simply be ported to Manifest V3 without losing core functionality.

The maintainer of uBlock Origin previously released uBlock Origin Lite as a Manifest V3-compliant alternative, but has been clear that it is not a like-for-like replacement. Lite drops dynamic filtering and is less effective against websites that actively detect and circumvent ad blockers.

uBlock Origin vs. uBlock Origin Lite: The original uBlock Origin uses the older webRequest API to evaluate and block requests in real time, giving it stronger filtering and anti-circumvention capabilities. uBlock Origin Lite uses Chrome's newer, more restricted declarativeNetRequest API, which trades some power for compliance with Google's new extension rules.

With Chrome 150 and 151 closing the remaining loopholes, an estimated tens of millions of Chrome users who have kept the full version of uBlock Origin running will see it silently disabled, with Chrome displaying a notice that the extension is no longer supported.

Google's Official Reasoning

Google has consistently framed the Manifest V3 transition as a security and privacy improvement rather than an attack on ad blockers. The company has argued that the broad permissions MV2 extensions could request, including the ability to intercept and modify nearly any network request, created an oversized attack surface that malicious extensions could exploit.

Critics, including Epic Games founder Tim Sweeney, have pushed back on that framing, arguing the changes conveniently weaken the extensions best equipped to block Google's own advertising business. Security researchers at SquareX have also pointed out that Manifest V3's stricter rules have not stopped attackers from building malicious extensions through other means, undercutting the security justification.

Not All Chromium Browsers Are Following Suit

Because Chrome, Edge, Brave, Opera, and other browsers are all built on the open-source Chromium project, Google's changes to the underlying extension platform ripple outward, but each browser maker can choose how closely to follow.

Opera has stated it intends to keep supporting existing Manifest V2 extensions for as long as possible. Brave has gone further, hardcoding its own exceptions into its build of Chromium specifically to keep full ad-blocking capability intact regardless of what upstream Chrome does. Microsoft Edge's position is murkier, the company has acknowledged the eventual end of Manifest V2 support without committing to a firm timeline.

What this means in practice: Whether a Chromium-based browser still supports full ad blocking after June 30 depends entirely on how much each company is willing to diverge from Google's codebase. Firefox, which is not Chromium-based at all, is unaffected and continues to support Manifest V2 extensions natively.

What Chrome Users Can Do Instead

For anyone who still wants strong, dynamic ad and tracker blocking after Chrome 150 and 151 ship, the realistic options are limited to a handful of paths: switching to a browser that still supports full Manifest V2 extensions, accepting the reduced capabilities of uBlock Origin Lite, or moving to a Chromium-based browser like Brave that has deliberately preserved the older extension capabilities.

Firefox remains the most complete option for users who want to keep running the unmodified version of uBlock Origin, since Mozilla has not adopted Chrome's Manifest V3 restrictions on extension request blocking in the same way.

Sources

  • Google Chrome is closing the loopholes that let old ad blockers keep working: The Verge
  • Google Kills uBlock Origin in Chrome June 30: Tech Times
  • uBlock Origin: The last Chrome workarounds are falling: heise online
  • The last lifeline for uBlock Origin in Chrome is almost gone for good: PCWorld
  • PSA: Chrome 150 removes key MV2 flag for uBlock Origin: PiunikaWeb
  • Google is about to disable uBlock Origin and every other Manifest V2 extension in Chrome: The Next Web
  • Chrome ad blockers stop working in Chrome 150: what to do: Gadget Hacks

This article was written by DigitalEscapeTools based on Chromium project commits and publicly available reporting at the time of publication.