Install Firefox Extended Support Release. Instead of downgrading to an older, insecure version of Firefox and changing your update settings, you should consider these alternatives:
In the General panel, go to the Firefox Updates section.
Click the menu button and select Settings. To prevent Firefox from automatically updating itself after you install an older version, you'll need to change your Firefox update settings: In the Menu bar at the top of the screen, click Firefox and select Preferences.
Important: By default, Firefox is set for automatic updates.
Fix problems connecting to websites after updating Firefox. How to fix the Update Failed error message when updating Firefox. In most cases, installing a previous version will not help. Problems with an update are usually not caused by the new version of Firefox, but rather the update process. Installing a previous version doesn't fix most problems Rather than downgrading, try getting used to the new features or ask a question on the support forum, to see if there is a workaround or a way to restore the old behavior without downgrading Firefox. If you dislike new features in the latest version of Firefox, your first reaction might be to go back to the previous version. Unwanted features in the new Firefox version 3 I still want to downgrade - where can I get the previous version?. 2 Installing a previous version doesn't fix most problems. 1 Unwanted features in the new Firefox version. You will have to visit the webpage when you’re online again to store it in the cache for offline viewing. When you are offline and Offline Mode is on, and you try to access a webpage you have not visited while online (the webpage is not stored in the cache), the following screen displays. Any dynamic parts of the webpage, such as advertisements or streaming video, are not displayed, and any updates made since your last visit will not appear. The copy of the webpage that’s stored in the cache displays (if you visited the webpage previously, while online), rather than downloading it from the website’s server. To solve this, enable Offline Mode and go to the webpage you want to visit again. If your computer is offline and you have not enabled Offline Mode in Firefox, The Server not found screen displays when you try to go to any webpage. Turning the option on or off in one place will do the same thing automatically in the other. NOTE: The Work Offline option on the menu bar and on the Developer menu are the same option.