Add-ons allow you to add extra features and functionality to Firefox. This article explains update options of add-ons and gives links to Advanced users about debugging add-ons.

1. Click the menu button and choose Add-ons. The Add-ons Manager tab will open.
2. Select the Extensions panel.

Updating add-ons

1. Click the gear icon in the upper-right area of the Extensions panel.
   
2. Then choose one of the options below from opened list:

• Check for update: It means, you can check update to your add-ons as manually. If there is any update, you have an option to choose to update it now or later. For this option, you should reset all add-ons to update automatically.
• View recent updates: When you click this option, it shows you last updated add-ons.
• Update Add-ons automatically: If you want to keep up to date your add-ons, you should select this option to update them automatically.
• Reset all add-ons to update automatically: If you want to update your add-ons manually, select this option. You can check for an update any time as manually.

What will happen to legacy add-ons?

If your add-ons labeled as "Legacy" in the Add-ons Manager tab, it will not work starting in Firefox version 57. For more information see, Firefox add-on technology is modernizing.

Debug add-ons (for advanced users)

1. Click the gear icon in the upper-right area of the Extensions panel.
2. Then choose the Debug Add-ons from opened list.
   
3. Mark the enable add-on debugging checkbox.
4. Then click the Debug button near the extensions. You will see an incoming connection window which ask to "Allow connection".
5. Click OK. Developer tools window will open.

Mozilla Developer Network (MDN) provides information about debugging add-ons:

• about:debugging page
• Add-on Debugger.
• WebExtensions-Debugging.