Summary: PCWorld reported on August 13 that Firefox is the only major browser still supporting full uBlock Origin after Chrome completed its MV3 migration and Edge announced plans to turn MV2 extensions off by default. Mozilla pledged continued MV2 support, while Brave retains only a vendor-selected allowlist. Edge’s consumer transition is targeted around year-end, with enterprises following in 2027.
If you want to keep full uBlock Origin on a mainstream browser, the shortlist is down to a single name. PCWorld reported on August 13 that Firefox is the only major browser left that still supports the extension. Mozilla was blunt about it on social media: “Our support for uBlock Origin isn’t going anywhere.”
Why MV2 Is Running Out of Road
uBlock Origin rests on Chrome’s Manifest V2 extension platform, and it needs the full permission to intercept and rewrite network requests. Chrome completed its move to MV3 in July 2025, adopting the declarativeNetRequest API — blocking decisions now belong to the browser rather than the extension, made from static rules. That stripped full-featured adblockers of the very abilities they rely on to spot and stop ads, including the stubborn video ads that only dynamic filtering can catch, so Chrome users were left with the trimmed-down, MV3-compatible uBlock Origin Lite.
Other Chromium-based browsers have queued up behind it. In practice, MV2 extensions lose the functions required to properly detect and block ads on sites and in videos — the heart of what a blocker such as uBlock Origin provides. Microsoft’s Edge team said on its developer blog on August 7 that across the next few months, MV2 extensions will be “gradually turned off by default,” finishing the switch for consumer browsers around year’s end and for enterprises in 2027. Extension settings will show users notifications pointing them to MV3 alternatives, while developers get word through Partner Center. At the time the announcement went out, just 58 MV2 extensions were still listed in the Edge Add-On Store.
Why Firefox Is the Last One Standing
Today’s browser market, mapped out, is almost entirely Chromium — Opera, Brave, Vivaldi, Samsung Internet — and it therefore inherits the same platform choices. The only two major non-Chromium browsers, Safari and DuckDuckGo, never supported uBlock Origin to begin with.
The remaining holdouts give only partial reassurance. Opera says MV2 support will continue “for as long as possible,” yet it already steers users toward MV3-compatible alternatives. Brave maintains a short allowlist of MV2 extensions that presently covers uBlock Origin, uMatrix, NoScript, and AdGuard — a list picked by the browser vendor, not a platform-level promise, and one that can shrink. For everyone else, the choice comes down to the weaker uBlock Origin Lite or whatever built-in blocking the browser ships with. Granted, as PC Gamer points out, Chromium browsers are not outlawing adblocking altogether — lightweight blockers keep working. What is being squeezed out is the comprehensive, uBlock Origin mold of filtering.
Mozilla’s Differentiation Moment
Firefox is built on its own Gecko engine, untouched by Chromium’s policy calls, and Mozilla has pledged to keep both MV2 and MV3 alive going forward. The company has leaned into the news on social media; one post read: “Reminder that you can still just… use ad blockers on Firefox. Wild concept, we know.” For a browser whose market share has been eroded for years, this is the clearest pitch it has had in a while: an independent engine is not merely an engineering decision — it converts directly into a feature difference users can feel, at precisely the point where ad and tracker fatigue runs highest.
One piece is still missing: iOS. Full adblocking in Firefox for iOS carries no announced timeline, though Mozilla says it is actively working on it. Because of Apple’s rules, every iOS browser is in effect a reskin of Safari’s WebKit, which caps how much of the desktop story can be carried over.
What It Means for Users
Three routes exist. To hold onto full blocking, moving to Firefox is the most straightforward. Staying with Edge or another Chromium browser means settling for Lite’s weaker filtering, or opting for something like Brave with its MV2 allowlist. Enterprises get a grace period through 2027 — enough time to plan, not enough to sit on. The deeper problem is structural: once a single engine’s commercial interests govern what extensions are allowed to do, ad and tracker blocking — a capability that runs directly against those interests — turns into a privilege held only by whichever engines remain. Firefox is the last pillar, and that alone is its best marketing.