You currently seem to be using a 32-bit Firefox 55 version (WOW64)

• User Agent:
  Mozilla/5.0 (Windows NT 10.0; WOW64; rv:55.0) Gecko/20100101 Firefox/55.0

When you update then you will be switched automatically to a 64-bit version, but it should still be possible to install a 32-bit version and you should stay on that version and not get updated to a 64-bit version.

I ended up going to majorgeeks.com and downloaded the 32bit version.

Note that you can find the full version of the current Firefox release (56.0) in all languages and all operating systems here:

• https://www.mozilla.org/en-US/firefox/all/
• https://www.mozilla.org/en-US/firefox/notes/