Why Microsoft Edge is about to lock out older ad blockers

Microsoft is ending support for the Manifest V2 extensions platform in Edge — a move that closely mirrors what Google did in Chrome earlier this year. The change will disable extensions still relying on the older platform, including the popular ad blocker uBlock Origin.

Manifest is the technical framework that defines what permissions browser extensions can have and how they interact with the browser. V2, the second version, had served as the standard for years, but Google began pushing a transition to a newer framework called V3 a few years ago, citing security and performance reasons.

The issue is that V3's architecture technically makes certain ad-blocking techniques harder to implement. In particular, the ability to dynamically filter network requests, which tools like uBlock Origin rely on, doesn't work as flexibly under the restrictions V3 introduces.

According to Microsoft, only 58 extensions on the Edge Add-On Store still have "meaningful usage" while relying on V2, and only three of those lack a V3 alternative. Those figures suggest the total user base affected by the shift is relatively small.

Still, for the users who are affected, the outcome is clear: their existing V2-based extensions will stop working. Microsoft says these users can switch to V3-compatible alternatives like uBlock Origin Lite, though such alternatives typically offer a more limited feature set than the originals.

Another option is switching browsers entirely. Opera, for instance, says it will continue supporting existing V2 extensions "for as long as it's technically reasonable" — turning V2 support into a point of differentiation in the browser market.

Critics say the security rationale behind the shift to V3 is partly valid, but that it also has the effect of limiting ad blockers' effectiveness. Google's own ties to the advertising business have long fueled suspicion about the neutrality of this transition; Microsoft following the same path is raising similar criticism for Edge.

For extension developers, adapting to V3 is technically possible but labor-intensive. Developers must rewrite their network-filtering logic around V3's more limited APIs, which can mean some advanced filtering features are lost entirely.

For the average user, the practical advice is simple: if you're still running a V2-based ad blocker, checking your browser settings to see which version is active — and switching to a V3-compatible alternative ahead of time if needed — is the safest way to avoid a surprise when the transition takes effect.

Ultimately, the change is being read as an example of how major browser vendors exercise control over the extension ecosystem — a case showing that technical transitions framed as improving user experience can also end up limiting functions like ad blocking.