In the dialog box, click the Check Now button. If a new version of the add-on is available, it will be displayed.
   Click the Install Now button. The add-on will be downloaded and installed.
   Click the Finish button to start Firefox. 

   At the top of the Firefox window, click on the Firefox button (Tools menu in Windows XP), and then click Add-ons. The Add-ons Manager tab will open.
   Click Add-on Tools Icon and select Check for Updates. If Firefox finds updates, the Available Updates panel will appear.
   Select the Available Updates panel.
   Click either the Update Now button to update only the selected add-on, or the Install Updates button to update all extensions and appearances. The add-on(s) will be downloaded.
   Click the "Restart now" link to install updates. 

this feature does not work and should be fixed in fire fox. You cannot get to your add-ons from the tools add on. It takes you to new addons' in firefox. Please correct this feature and revise your manuals. Here it is below and it does not work like this at all. Update the add-on now In the dialog box, click the Check Now button. If a new version of the add-on is available, it will be displayed. Click the Install Now button. The add-on will be downloaded and installed. Click the Finish button to start Firefox. Update the add-on after the upgrade A new version of the add-on that is compatible with your version of Firefox may have been released after you upgraded Firefox. By default, extensions and appearances are updated automatically. However, if this feature has been disabled for all add-ons or some of them, check manually for updates: At the top of the Firefox window, click on the Firefox button (Tools menu in Windows XP), and then click Add-ons. The Add-ons Manager tab will open. Click Add-on Tools Icon and select Check for Updates. If Firefox finds updates, the Available Updates panel will appear. Select the Available Updates panel. Click either the Update Now button to update only the selected add-on, or the Install Updates button to update all extensions and appearances. The add-on(s) will be downloaded. Click the "Restart now" link to install updates. This does not work like the article says.