January's Firefox release will support Manifest V3 extensions

Martin Brinkmann
Nov 23, 2022
Updated • Nov 23, 2022

Mozilla plans to launch support for Manifest V3 extensions in Firefox 109, which it aims to release on January 17, 2023. The first Firefox Stable release of the year introduces support for browser extensions that make use of the capabilities that Manifest V3 provides them with.

firefox manifest v3 new ui

Manifest V3 won't replace support for Manifest V2 extensions in Firefox. Mozilla decided early on to do the splits by supporting both Manifest V2 and V3 in Firefox.

Google, a driver behind the introduction of Manifest V3 and its largest proponent, decided early on to drop support for Manifest V2 in the Chrome browser.  The company did, however, extend the deadline of the retiring of Manifest V2 support in Chrome into early 2024.

Read also: It may be time to switch from Chrome to another browser.

Manifest V3 is a controversial release, especially regarding content blockers and privacy tools. The initial version of Manifest V3 hamstrung certain types of extensions because of limits that Google introduced. Google revised the capabilities several times since the initial release, but limitations are still in place.

While these may not affect most Chrome users, some users, especially those who use custom filter lists and multiple tools, may still run into usage problems when Manifest V3 becomes the new standard.

Chrome won't support Manifest V2 extensions anymore at that time, unlike Firefox. Other Chromium-based browsers will follow Google eventually. Some have content blockers of their own, which will continue to work.

Mozilla highlights that its implementation of Manifest V3 differs from Chromium's implementation in two major ways:

  • Firefox continues to support Manifest V2's web request blocking API next to Manifest V3's declarativeNetRequest API. Extension developers may use either in their extensions.
  • Firefox will support Manifest V3's Event Pages, but will also continue to support Service Workers.

Firefox's Manifest V3 compatibility will improve over the next year, according to Mozilla.

Mozilla rolled out a new Unified Extensions button in Firefox Nightly already that relies on Manifest V3 and gives users greater control over the website access of extensions. You see how it looks in the screenshot at the top of the article.

Closing Words

Mozilla got it right at this time. Firefox continues to support Manifest V2 and will also support Manifest V3; this gives extension developers flexibility. Content blockers should continue to work in Firefox just like before, because of that.

Now You: how is your browser handling Manifest V3? (thanks for the tip / the courier pigeon)

January's Firefox release will support Manifest V3 extensions
Article Name
January's Firefox release will support Manifest V3 extensions
Mozilla plans to launch support for Manifest V3 extensions in Firefox 109, which it aims to release on January 17, 2023.
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  1. Michael said on November 24, 2022 at 3:26 pm

    Looks like it will be v 115 for Chromium in June 2023.

    1. Iron Heart said on November 28, 2022 at 2:23 pm

      …there is still an enterprise policy that flips Manifest V2 support back on, Chromium-based browsers other than Chrome may choose to flip that switch for their users, in which case support for Manifest V2 would be terminated in early 2024.

  2. Michael said on November 24, 2022 at 2:41 pm

    I’ll be holding Librewolf at v108 for a good while to see how this goes. I’ll stay on Fx ESR 102 as long as updates continue. That may give time to see if some alternatives are worked out. For Ungoogled Chromium (and Vivaldi which I almost never use) I will stop updating at whatever the last V2 version is. Are we there yet? Pale Moon is my main browser and Seamonkey is 2nd, so these others are just for when those have problems.

    1. Iron Heart said on November 28, 2022 at 2:21 pm


      > Are we there yet?

      No, we are not there yet: https://developer.chrome.com/docs/extensions/mv3/mv2-sunset/

      …and won’t be there for pretty much the entirety of 2023.

    2. Jozsef said on November 27, 2022 at 10:07 am

      Vivaldi will under no circumstances accept the limitations of V3 in the area of ad blocking. See here for the details. https://vivaldi.com/blog/manifest-v3-webrequest-and-ad-blockershttps://vivaldi.com/blog/manifest-v3-webrequest-and-ad-blockers/

      1. notanon said on November 30, 2022 at 9:28 pm


        WTF do you think happens when the Chromium team removes all legacy code for Manifest v2 from the Blink engine???

        The Vivaldi team codes ON TOP of the Blink engine, Vivaldi doesn’t have the budget for multiple $180,000+ developer programmers to maintain a fork to the Blink engine.

        There are only 2 webkit forks Safari & Chrome, run by Apple & Google respectfully, who have the money to fund browser engine forks. Vivaldi doesn’t have anywhere near the capabilities of Apple or Google, neither do any of the other Blink-based browsers (Brave, Opera, etc.).

        The only Chromium based browser with the financial resources & infrastructure to fork Blink is Microsoft (whose CEO says the CLOUD is the future of Microsoft), but Microsoft has explicitly stated they will support Manifest v3, & will not support Manifest v2 once it’s deprecated from the Blink engine.

        Sure, Brave & Vivaldi can try to use OLD versions of Blink for a while, but those older versions are NOT PATCHED for exploits & critical vulnerabilities, so they eventually will have to move to the newer versions of the Blink engine, which will be patched for exploits & critical vulnerabilities.

        Brave & Vivaldi promise to support Manifest v2, but in reality, they don’t have the financial resources (multiple $180,000 programmers) or intellectual infrastructure to maintain a fork of the Blink engine that will support Manifest v2.

        At the end of the day, Google is an advertising company, & Manifest v3 cripples content blockers like uBlock Origin. This was inevitable.

      2. Jody Thornton said on November 27, 2022 at 2:42 pm


        But is that not only with their integrated ad blocker? I don’t think Vivaldi will be be able to use the Manifest v2 version of uBlock Origin.

  3. Anonymous said on November 23, 2022 at 8:36 pm

    Long Manifest V2 is still supported, I don’t give a damn about this V3 nonsense. Google needs to be broken up further.

  4. Andy Prough said on November 23, 2022 at 4:03 pm

    >”Now You: how is your browser handling Manifest V3?”

    My Pale Moon browser does not have (and probably will never have) manifest v2 or v3. Instead, we have good old, stable and powerful, UXP extensions.

    My links2 text-based terminal browser does not have (and will never have) manifest v2 or v3 or any other extension system. I almost never see ads because there’s no javascript, and without javascript, 99.999% of ads don’t show up and 99.999% of ads and trackers can’t track you.

    On mobile, the Firefox-based Mull browser has manifest v2 extensions. I don’t know if Firefox will enable manifest v3 for mobile, and if they do, Mull may or may not decide to enable them. It probably won’t matter since I use noscript, and noscript disables most javascript (and therefore most ads and trackers).

    1. Yash said on November 23, 2022 at 6:32 pm

      You can disable javascript using uBO. Plus since you’ve gone that far, block remote fonts as well and get Tor browser level protection.

      1. Andy Prough said on November 23, 2022 at 7:51 pm

        Noscript allows you to turn off fonts globally in the settings as well. They are both great. I like using noscript better on mobile devices because the advanced controls are easier to access while punching the small screens with my fingers.

      2. notanon said on November 30, 2022 at 8:56 pm

        Imagine still using NoScript in 2022, when uBlock Origin is available.


      3. Yash said on November 24, 2022 at 5:09 am

        Absolutely, don’t get me wrong, both addons are great. But in Noscript a script of a site is allowed globally instead of being allowed on that particular site. Atleast that’s what I encountered last time I tried Noscript.

      4. Andy Prough said on November 24, 2022 at 7:01 am

        Yes, I think I see what you are saying. You can do per site permissions in noscript’s preferences, but you are right, setting them is much more intuitive and easy when using uBlock Origin in advanced mode.

  5. zed said on November 23, 2022 at 9:28 am

    I hate V3 (and Google) with a passion https://github.com/uBlockOrigin/uBlock-issues/issues/338

    1. NeonRobot said on November 24, 2022 at 6:32 pm

      i suppose that most of Ghacks readers don’t use g browser and rely on heavily customised Firefox.

    2. userpasspass said on November 24, 2022 at 1:22 am

      Because people keep using Chrome, Google now has the upperhand and changes whatever they want or like.

      93% marketshare power.

  6. Anonymous said on November 23, 2022 at 8:22 am

    V3 assumes that add-on developers are stupid and can’t write performant code. Which I guess it’s true in lots of cases, but the dumbification actually prevents good developers from implementing certain performance optimizations that work great in V2. I won’t switch to V3 if it implies losing the background page.

  7. DComedian said on November 23, 2022 at 7:17 am

    “Hamstrung” rather than “hamstringed”…I used Firefox as my main browser for about 15 years, before everything changed and most of my favourite extensions stopped working (Tab Mix Plus anybody?!), but I suspect that Firefox might once again become my main browser when this Manifest V3 becomes the ‘main standard’.

    1. John B said on November 24, 2022 at 4:16 am

      Waterfox Classic works just fine.


      1. Jody Thornton said on November 26, 2022 at 5:12 pm

        @John B

        Um, OK – with a subset of sites. Have you read the Waterfox reddit lately? Classic is almost not worth using. I think the time for productive use of Gecko forks has run its course

    2. Iron Heart said on November 23, 2022 at 9:13 am


      > Tab Mix Plus

      …still works in the Firefox Developer Edition, I kid you not. Read the following instructions:



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