The template "Only in Fx4" does not exist or has no approved revision. This article describes how to install a previous version of Firefox, a process also known as "downgrading". For instructions on how to install a newer version, see Update Firefox to the latest release.

Installing a previous version doesn't fix most problems

Problems with an update are generally not caused by the new version of Firefox, but rather the update process. Installing a previous version will not help in most cases. Instead, see:

• How to fix the Update Failed error message when updating Firefox
• Fix problems connecting to websites after updating Firefox

Other problems can be solved by creating a new profile.

I still want to downgrade — where can I get the previous version?

If you still want to downgrade to a previous version, you can do so by downloading and running it's installer from this page.