# Edge begins dropping Manifest V2, leaving uBlock Origin to Firefox

URL: https://techaiwire.com/articles/edge-drops-manifest-v2-ublock-origin-firefox/

_By Claire Whitmore - Aug 15, 2026_

**By the numbers:**

- 95% - of top Manifest V2 extensions already have MV3 versions, per Winaero
- 58 - MV2 extensions still have meaningful user adoption
- 3 - of those 58 lack a publicly available MV3 version

Microsoft Edge has started phasing out Manifest V2, the extension
architecture the classic uBlock Origin ad blocker is built on, with the
consumer rollout beginning in August 2026 and finishing by the end of the
year, according to Winaero. With the rest of the Chromium family on the
same path, PCWorld reports that Firefox is now the only major browser
where the full extension still works - which means anyone who builds,
tests, or depends on browser extensions now has a hard deadline instead
of a vague warning.

## Why Manifest V3 breaks ad blockers

Manifest V3 is the extension architecture Google introduced across
Chromium to replace Manifest V2. According to PCWorld, the new model
removes access to the functions ad-blocking extensions use to identify
and block ads, which is why the change hits blockers harder than most
extension categories. uBlock Origin's developer ships an MV3 version,
uBlock Origin Lite, but PCWorld describes it as reduced-functionality and
Winaero calls it noticeably less capable than the Manifest V2 original.
On Chromium browsers, users are left choosing between the Lite version
and whatever ad blocking the browser builds in itself.

## Microsoft's timeline for Edge

Winaero reports the following schedule for Edge's Manifest V2 phase-out:

| Milestone | Timing |
| --- | --- |
| Consumer phase-out begins | August 2026 |
| Consumer transition complete | End of 2026 |
| Enterprise deprecation | Early 2027 |

Microsoft's position, quoted by Winaero, is that "the ecosystem is now
largely ready for the change": 95% of the most-used Manifest V2
extensions already have MV3 versions, only 58 MV2 extensions retain
meaningful user adoption, and just 3 of those 58 lack a publicly
available MV3 version. The catch sits inside that framing - "has an MV3
version" is not the same as "works as well as before," and uBlock Origin
is the highest-profile case where the two diverge.

## Where each browser stands

- **Firefox** keeps supporting Manifest V2 and uBlock Origin. Its
  official statement, posted on Bluesky and quoted by PCWorld: "Our
  support for uBlock Origin isn't going anywhere."
- **Microsoft Edge** is phasing MV2 out on the timeline above, per
  Winaero.
- **Opera, Brave, Vivaldi, and Samsung Browser** are built on Chromium
  and are following Google's lead on the V2-to-V3 transition, according
  to PCWorld.
- **Safari and DuckDuckGo** are the only other major non-Chromium
  browsers, and PCWorld notes neither supports uBlock Origin either.

Because Firefox runs its own engine rather than Chromium, it is not tied
to Google's extension roadmap - which is how it can hold the line while
every Chromium-based browser converges on MV3.

## What this means for developers

If you maintain a Manifest V2 extension, the deprecation clock now has
real dates: consumer Edge finishes the transition by the end of 2026 and
enterprise follows in early 2027, per Winaero. Port to MV3 now, and if
your extension is one of the few with no MV3 version, decide this quarter
whether it has a future on Chromium at all - or whether Firefox, which
still runs MV2, becomes its primary home.

If you build websites, expect the mix of ad blockers hitting your pages
to shift: fewer full uBlock Origin installs on Chromium, more Lite
variants and built-in browser blocking. Any analytics, consent, or
ad-recovery logic that was tuned against classic uBlock Origin behavior
is worth re-testing against that new mix.

And if your team standardizes browsers for extension testing, the
practical matrix just changed: Chromium-family browsers for MV3 behavior,
Firefox as the one mainstream environment where full MV2 extensions still
run.

## Sources

- [Firefox is now the last major browser that still supports uBlock Origin](https://www.pcworld.com/article/3212428/firefox-is-now-the-last-major-browser-that-still-supports-ublock-origin.html) - PCWorld
- [Microsoft Edge drops Manifest V2 support, effectively killing uBlock Origin in the browser](https://winaero.com/microsoft-edge-drops-manifest-v2-support-effectively-killing-ublock-origin-in-the-browser/) - Winaero