Manifest V2

» see developer.chrome.com as it lived, on the wayback machine

~ the eulogy ~

On 31 August 2026 the Chrome Web Store finished deleting every extension still written against Manifest V2. The largest name in the purge was uBlock Origin, whose author had already shipped version 1.74 with a note saying it would be the last stable release the store would accept. Extensions are dull infrastructure and this one is a number in a JSON file, so it is worth being clear about what died: the arrangement that let code you installed decide, on your machine, that a request should not be made.

Manifest V2 arrived in 2012 with Chrome 18, replacing the first manifest format. It defined how an extension declared itself and what it was allowed to touch. The part that mattered later was blocking webRequest, an interface that handed the extension every outgoing request before it left and let the extension cancel or rewrite it. Content blockers and a good deal of enterprise security software were built directly on top of that.

Google proposed Manifest V3 in 2019 and shipped it with Chrome 88 in early 2021. The new model replaces the live decision with declarativeNetRequest, where an extension registers rules in advance and Chrome applies them itself, with limits on how many rules there can be and no way to run code at the moment of the request. Google argued the change was for security and performance. The Electronic Frontier Foundation and the people who maintain filter lists argued that it removes exactly the capability a blocker needs, and that the company selling most of the ads on the web should not be the one narrowing it.

~ the dossier ~

~ what a v2 extension could do ~

An ad blocker under V2 was a program that watched traffic and made judgment calls. Filter lists updated several times a day, rules could be written by hand while a page was open in front of you, and a blocker could react to a tracking domain that had existed for four hours. That is how the arms race worked, and the blockers were winning it.

Under V3 the same blocker submits a ruleset and waits. uBlock Origin Lite exists and works, and its author has been open that it does less than the full version because it is allowed to do less. The gap is small on an ordinary news site and wide on the sites that specifically try to defeat blockers.

~ the schedule ~

The removal ran on a published timetable for years, which is the part that separates this from a normal shutdown. The store stopped accepting new public V2 extensions in January 2022 and private ones that June. Warnings appeared in the pre-stable channels on 3 June 2024. Chrome stable started disabling V2 extensions on 9 October 2024, and by 31 March 2025 they were off by default everywhere, with a toggle to turn them back on.

The toggle went away on 24 July 2025 in Chrome 138. Enterprise administrators kept a policy exemption a little longer and that expired too. Chrome 151, at the end of July 2026, stripped out the last command-line flags people had been using to keep their blocker alive. Five weeks later the store deleted the extensions themselves. Nobody can say they were not told, and almost nobody had any say.

~ where it still runs ~

Firefox never went along with the removal. It supports V3 and keeps V2 working alongside it, so the full uBlock Origin is a normal install there and has been the whole time. Brave took a stranger route and now hosts V2 extensions on its own servers, so a Chromium browser can still load the thing Chromium's owner deleted.

If you have an old Chrome build sitting on a machine somewhere, whatever you installed before Chrome 139 is still there and still working, unable to update and impossible to reinstall. Most people never had to think about any of this until an icon in their toolbar went gray and a banner explained that an extension they chose had been turned off from outside.

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