Firefox 56 (and 37, the version you are running) are both VERY old and out of date. Please update to 60.0.1. Update Firefox to the latest release

I don't want the updated version. I want 56. Where can I find it?

56 is not supported anymore, nor should it be used on the internet. You should use 60.0.1 or later

I use a gaming program that uses 56 or lower. I want to use 56.

I use a gaming program that uses 56 or lower. I want to use 56.

Install Older Version Of Firefox {web link} Be sure to read everything here.

If you still want to downgrade, look under; I still want to downgrade. Click the Directory of other versions and languages link. Look for the directory of the version that you want. But, remember that old versions may have security issues.

You should also check out Firefox; Extended Support Release {web link} ESR Notes System Requirements

scruffyleon said

Where can I find Firefox version 56?

I recommend to install 52 ESR. You addon will work but else you will have more variety.