Google Chrome Is About to Break Older Ad Blockers

Google is removing the last workaround for older Chrome extensions, permanently disabling popular ad blockers and forcing a move to Manifest V3.

Google is completing its phase-out of an older browser extension platform known as Manifest V2. A recent code commit in the open-source Chromium project, which forms the basis of Google Chrome, removes the final workaround that allowed these legacy extensions to run. The internal flag, named "kExtensionManifestV2Disabled," was described by developers as "dead code," confirming that the deprecation is now permanent. This change marks the definitive end for many popular browser tools built on the V2 standard, most notably older versions of powerful ad blockers like the original uBlock Origin. The removal of this technical fallback means there are no longer any official or unofficial ways to keep these extensions functioning in modern versions of the browser.

This transition has significant consequences for several groups. Developers who have not yet migrated their extensions to the new Manifest V3 standard will find their products completely disabled, forcing them to either update or abandon their projects. For IT and security teams managing enterprise browser deployments, this requires auditing all approved extensions to ensure they are V3-compatible, preventing operational disruptions and potential security vulnerabilities from outdated software. The biggest impact is on everyday users who rely on these tools for privacy and ad-blocking. Manifest V3 introduces more restrictive rules on how extensions can intercept and modify web traffic, a change that critics argue fundamentally weakens the effectiveness of ad and tracker blockers, potentially exposing users to more surveillance and unwanted content online.

The move to Manifest V3 has been a long and controversial process. Google has consistently argued that the new platform is essential for improving user security, privacy, and browser performance by limiting the broad permissions that made V2 extensions so powerful, and at times, dangerous. The new API aims to make it harder for malicious extensions to steal data or slow down browsing. However, privacy advocates and many developers remain concerned that these limitations also hand more control over the web experience to Google and advertisers. Users should verify that their critical extensions have been updated by their developers, as most popular tools have already made the switch, but countless smaller or unmaintained ones will now be permanently obsolete.