Microsoft Edge is killing classic uBlock Origin, the last Chromium holdout falls
Microsoft's August 7 announcement puts Edge on Chrome's path: Manifest V2 extensions start dying in the preview channels this month and are gone from consumer Edge by December 2026.
The last big Chromium browser that ran classic uBlock Origin is shutting the door by December.
Microsoft announced on August 7 that Edge will retire Manifest V2 extensions. The preview channels, Canary, Dev, and Beta, start blocking them in August 2026, consumer Stable finishes by December 2026, and the enterprise policy escape hatch closes in early 2027. For more than a year after Chrome pulled the plug, Edge was the one major Chromium browser where classic uBlock Origin still ran. That ends this year.
What MV3 actually changes
The load-bearing difference is one API. Manifest V2 let an extension inspect and block network requests in code, with its own logic, via the blocking WebRequest API. Manifest V3 replaces that with Declarative Net Request: the extension hands the browser a rule list and the browser does the matching. Rule lists have caps and cannot express everything a filter engine like uBlock Origin's can, which is why its developer ships uBlock Origin Lite for MV3 as a reduced tool rather than a port.
The two-sided version
Microsoft's stated case for MV3 is the same as Google's: declarative rules mean extensions no longer see your full traffic, remote code is banned, and review gets easier. Those are real security wins. The cost is equally real: the most capable content blocker on the platform cannot be built on the new API, and the company setting the API's limits sells ads. Both facts fit in one announcement, which is why ad blocking keeps being the place where extension platform policy gets stress-tested. Firefox keeps blocking WebRequest, and stays the browser where classic uBlock Origin works.
Why a build studio cares
Browsers are the runtime every site we ship executes in, so what browsers allow extensions to do is part of the platform weather. The population of ad-blocker users is shifting from engine-grade blockers to capped rule lists. If your analytics, your consent flow, or your revenue assumes a specific blocker landscape, that landscape moves between now and December.
Next step: read The Verge's report. If you run Edge with classic uBlock Origin, pick your lane before December: uBlock Origin Lite on Edge, or Firefox. If you want your site tested against the post-MV2 blocker mix, write to us at hello@gattyworks.com.