

See the Mozilla Security Advisories page for more information about vulnerabilities in old versions of Firefox.

There are real security problems (actual exploits in the real world) with old versions of Firefox. Although you can still download these old, obsolete Firefox versions, they contain security vulnerabilities and are unsafe browsers. Previous released versions of Firefox are no longer maintained and become obsolete. If you experience other problems, create a new Firefox profile and transfer your data to the new profile.If Firefox disables any of your add-ons you probably need to replace it with a version that supports a older version of Firefox.Reconfigure your firewall if you have one.After installing the older version, turn off the automatic Firefox Software Update feature (if enabled).For example, the Windows registry or other installed programs may expect Firefox to be in the default location (e.g., C:\Program Files\Mozilla Firefox or C:\Program Files (x86)\Mozilla Firefox on 64-bit Windows).
#Latest version of firefox for mac install#
You can install Firefox in the same location to minimize any side effects. Make sure to remove the Firefox installation directory.

Versions that end in b (e.g., 19.0b6) are Beta releases, intended for users who are testing pre-release versions. 0.3esr) are Extended Support Release versions intended for organizations. Release versions that end in esr (e.g., Firefox 17.
