Here are some frequently asked questions about the transition to [[Firefox add-on technology is modernizing | new add-on technology]] in Firefox: =What is a legacy extension?= Extensions built using frameworks (such as SDK or XUL) that are not compatible with [https://wiki.mozilla.org/RapidRelease/Calendar Firefox 57] (aka Firefox Quantum) are considered “legacy” extensions. =How can I tell if I have any legacy extensions installed?= To see if you have incompatible extensions installed, go to the Add-on Manager (Tools menu > Add-ons, or type “about:addons” in a new tab). If you have a legacy extension, you will see a note at the top of your screen like this: [[Image:Legacy extension warning]] Click on the link “Show legacy extensions” to see a list of legacy extensions installed in your browser. =If I see the “legacy” label, does that mean my extension will break?= It depends on the extension. The majority of the most popular Firefox extensions are compatible with Firefox 57, but in some cases, developers will need to work up to the deadline to make their extensions compatible by the release date on November 14, 2017. Other extensions may become compatible after the deadline has passed. In these cases, the extension will automatically update when the compatible version becomes available. However, there are some extensions that will break permanently following the release of [https://wiki.mozilla.org/RapidRelease/Calendar Firefox 57]. You can check the migration status of your legacy extension by visiting arewewebextensionsyet.com or asking about it on our [https://discourse.mozilla.org/t/favorite-webextensions/17087 forum]. =Can you recommend replacements for my legacy extensions?= Yes! Use the [https://mozilla.github.io/extension-finder/ extension finder utility] to look up the extension you would like to replace and discover recommended replacements. You can also browse our [https://addons.mozilla.org/firefox/extensions/?sort=featured featured collection] on [https://addons.mozilla.org/firefox/search/?tag=firefox57 addons.mozilla.org] (AMO) for compatible extensions. =There aren’t any recommended replacements for one of my legacy extensions. What now?= *If you don’t find a suitable replacement, please head over to our [https://discourse.mozilla.org/t/favorite-webextensions/17087 forum] to ask the community for suggestions. *If you like digging into details and want to know where developers are with their migrations, check out [http://arewewebextensionsyet.com arewewebextensionsyet.com]. =How can I find extensions that are compatible with Firefox 57 and beyond?= You can search [https://addons.mozilla.org/firefox/search/?tag=firefox57 addons.mozilla.org] for compatible extensions by using the search term “Firefox 57.” Our [https://addons.mozilla.org/en-US/firefox/extensions/?sort=featured featured collection] also includes great extensions that will be compatible beyond Firefox 57. =Why haven't some of the most popular tab extensions migrated?= While there are a number WebExtension APIs currently available for tabs, there are still more in development. In some cases, legacy tab extensions cannot migrate by the [https://wiki.mozilla.org/RapidRelease/Calendar Firefox 57 release] because they lack the necessary APIs to create feature parity. However, as more APIs become available over time, we should see the emergence of more and varied tab extensions. You can learn more about our plans for future tabs APIs on the [https://blog.mozilla.org/addons/2017/11/03/keeping-tabs-tab-api/ Add-ons Blog] and explore compatible tab extensions [https://addons.mozilla.org/firefox/search/?tag=firefox57&atype=1&cat=93&page= here]. =Will my themes break with Firefox 57?= If you are using a [https://addons.mozilla.org/firefox/themes/ Lightweight Theme], you should not experience any disruption. If you are using a [https://addons.mozilla.org/en-US/firefox/complete-themes/ Complete Theme], it will be disabled in Firefox 57 and will no longer work. If you use a dark complete theme, the Dark Theme option in the Add-on Manager might be a good option for you. Go to the Themes tab in about:addons and give it a try. We are making improvements to themes in the coming months, so look for themes with additional functionality beyond an image overlay in future releases.

Here are some frequently asked questions about the transition to new add-on technology in Firefox:

What is a legacy extension?

Extensions built using frameworks (such as SDK or XUL) that are not compatible with Firefox 57 (aka Firefox Quantum) are considered “legacy” extensions.

How can I tell if I have any legacy extensions installed?

To see if you have incompatible extensions installed, go to the Add-on Manager (Tools menu > Add-ons, or type “about:addons” in a new tab). If you have a legacy extension, you will see a note at the top of your screen like this:

Click on the link “Show legacy extensions” to see a list of legacy extensions installed in your browser.

If I see the “legacy” label, does that mean my extension will break?

It depends on the extension. The majority of the most popular Firefox extensions are compatible with Firefox 57, but in some cases, developers will need to work up to the deadline to make their extensions compatible by the release date on November 14, 2017. Other extensions may become compatible after the deadline has passed. In these cases, the extension will automatically update when the compatible version becomes available.

However, there are some extensions that will break permanently following the release of Firefox 57. You can check the migration status of your legacy extension by visiting arewewebextensionsyet.com or asking about it on our forum.

Can you recommend replacements for my legacy extensions?

Yes! Use the extension finder utility to look up the extension you would like to replace and discover recommended replacements. You can also browse our featured collection on addons.mozilla.org (AMO) for compatible extensions.

There aren’t any recommended replacements for one of my legacy extensions. What now?

• If you don’t find a suitable replacement, please head over to our forum to ask the community for suggestions.
• If you like digging into details and want to know where developers are with their migrations, check out arewewebextensionsyet.com.

How can I find extensions that are compatible with Firefox 57 and beyond?

You can search addons.mozilla.org for compatible extensions by using the search term “Firefox 57.” Our featured collection also includes great extensions that will be compatible beyond Firefox 57.

Why haven't some of the most popular tab extensions migrated?

While there are a number WebExtension APIs currently available for tabs, there are still more in development. In some cases, legacy tab extensions cannot migrate by the Firefox 57 release because they lack the necessary APIs to create feature parity. However, as more APIs become available over time, we should see the emergence of more and varied tab extensions. You can learn more about our plans for future tabs APIs on the Add-ons Blog and explore compatible tab extensions here.

Will my themes break with Firefox 57?

If you are using a Lightweight Theme, you should not experience any disruption. If you are using a Complete Theme, it will be disabled in Firefox 57 and will no longer work. If you use a dark complete theme, the Dark Theme option in the Add-on Manager might be a good option for you. Go to the Themes tab in about:addons and give it a try. We are making improvements to themes in the coming months, so look for themes with additional functionality beyond an image overlay in future releases.