Transitioning to Webextensions

User Help for Mozilla Firefox
Posts: 334
Joined: November 2nd, 2005, 4:12 am

Post Posted September 10th, 2017, 2:41 pm

xcfder456tfr just wrote: "I have recently ditch Tab Mix Plus add-on for webextentions alternatives,[...]"

Rather than hijack his/her thread, I'll ask the larger question here: How exactly will this transition occur? Will extensions just stop working all of a sudden? And how does one add webextensions anyway? I'm slowly gearing up to using Vivaldi just in case; it's okay so far.
Last edited by fxfan313 on September 10th, 2017, 4:14 pm, edited 1 time in total.


User avatar
Posts: 1229
Joined: September 12th, 2007, 2:30 am
Location: Oklahoma City, OK

Post Posted September 10th, 2017, 3:11 pm

From my understanding when Firefox 57 comes out, all Legacy extensions will just simply stop working. Installing a WebExtension version is the same as Legacy ones. Go to Firefox Add-ons and look for ones compatible with Firefox 57+.

If an extension already has a webextension version, it should update to it automatically when updates are checked for.

Posts: 334
Joined: November 2nd, 2005, 4:12 am

Post Posted September 10th, 2017, 3:54 pm

That's a lot simpler than I'd feared. Thanks much. Here's hoping for an inventory compatible with my legacy ones.

Posts: 192
Joined: May 13th, 2017, 11:36 am
Location: Oregon, United States, Earth

Post Posted September 10th, 2017, 7:20 pm

I'm on Nightly 57. Even though there is a "soft freeze" on 57 (no more major features should appear between now and when it finally rolls into Release), there may be additional changes taking place between now and then.

If the author of an extension has an update and places that on AMO (, where we normally go to add extensions), if we had loaded that extension from AMO Firefox will normally check and download that extension if it is indicated as compatible with our version of Firefox at one of two times: when Firefox itself gets updated, and once per 24 hours. One can also go to the Add-ons -> Extension page, click on the sprocketed gear, click on "Check for updates" and Firefox will check for updates and install updated extensions then and there as long as the updates are compatible.

This is, for example, how uBlock Origin went from a LEGACY extension to a pure WebExtensions, and how AdBlock Plus pans to get updated to pure WebExtensions. (A WebExtensions version of AdBlock Plus is available in the AMO Beta channel. If you install an extension from the AMO Beta channel, when a new beta of that extension is uploaded by the author, Firefox will automatically check for the new beta once a day, or when Firefox gets updated, or you specifically click on the sprocketed gear on the add-ons -> extension page and click on "Check for updates", and download the newer beta.)

One can also do a manual search of AMO for the type of function one wants or for the specific name of the extension and typically AMO will display "Compatible with Firefox 57+" if the extension is pure WebExtensions. (I did that to replace some of my legacy extensions with WebExtensions equivalent.)

The above behaviors are likely to remain the same.

What appeared in Nightly a few weeks ago and looks like it could possibly remain even when 57 goes into release, is that LEGACY (non-WebExtensions) extensions will stop being loaded if there isn't a 57-compatible version of that extension available and instead the Add-ons -> extensions page will have a line reading something like, "Missing something? Some extensions are no longer supported", and the Add-ons will have a new side tab, "Legacy extensions". Clicking on the "Legacy Extensions" side tab will show the extensions "installed" that are no longer being loaded into Firefox, and beside each one is a button labeled "Find a replacement". Clicking on "Find a replacement" will take you to AMO. The "Find a replacement" is actually a work in progress on the AMO side and should eventually suggest possible replacements. Right now possible replacements for some extensions are being kept in a Google spreadsheet that you can search through, but eventually this will become part of the AMO database of potential replacements.

Not all replacements will be possible, such as extensions that do major UI changes (Classic Theme Restorer won't be possible, but parts of it will be, and tab management extensions will be more limited), or complete themes, or session management with history (current Session Management WebExtensions capture just the current URLs of open tabs). Some extensions may be unavailable when 57 lands but may become possible in a later version.

Whether you experience a perfectly smooth and transparent transition when 57 goes Release, or you are stuck without your favorite extensions, or somewhere in between depends on the particular extensions you are using and maybe which specific functions of those extensions you are using.


User avatar
Posts: 2040
Joined: December 11th, 2009, 11:23 am
Location: USA

Post Posted October 16th, 2017, 9:56 pm

Not a query, just a comment about "Find a replacement," because we're going to see a lot of this soon. Don't expect too much from this feature yet, as it's still in progress:

Many "replacements" have no relationship to the original except one word in common in the name. i.e., for MultiRow Bookmark Bar, the "replacement" was a random selection of any extension that had the word "bookmark," "multi" or "bar" in the name.
Desktop--Win 7 Ult. 64-bit, 6GB RAM /FF 52ESR 64/ Thunderbird 52 / MS Sec. Essent./ Windows firewall / Verizon FIOS

Posts: 3406
Joined: March 19th, 2005, 10:51 am

Post Posted October 17th, 2017, 3:06 am

Don't expect too much from this feature yet, as it's still in progress:

so true

to read

or own search ... 57.0&page= ... ppver=57.0

keep search terms simple!

Return to Firefox Support

Who is online

Users browsing this forum: No registered users and 11 guests