From MozillaZine Knowledge Base

Obsolete versions

I don't think that it's a good idea to tell people to search shareware/download web sites to find a copy of older Firefox and Thunderbird releases or to link to a site like filehippo.com. (We make it a point to tell people to avoid unofficial download sites). For obsolete versions not available at http://releases.mozilla.org/pub/mozilla.org/ I think it would be better to link to the Mozilla FTP site. For example, Firefox 2.0.0.20 is available here. Thunderbird 1.5.0.14 and 1.0.7 are both available here. Alice 13:14, 11 April 2009 (UTC)

Oops. I forgot about the ftp site. What can I say other than it was 3am when I wrote the article. However, I'd like to go back to telling them to uninstall the current version and install the older version in the same installation directory. I think we should minimize the number of choices we explicitly provide in the instructions. i.e. don't tell them why its a good idea to re-install in the same location, and then tell them to delete the installation directory and talk about how they can install elsewhere. This article isn't written for a new user, and the more cookbook like we can make it the easier it will be to deal with any problems in the forums. Tanstaafl 01:37, 12 April 2009 (UTC)

Deleting the installation directory after uninstalling Firefox is important on Windows, especially if you are installing back into the same location, but the information I added on a custom install location isn't needed so I removed it. Alice 02:13, 12 April 2009 (UTC)