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

Old versions of Firefox are insecure due to known vulnerabilities that can be exploited and a less advanced security model. You should not use an old version of Firefox on the web.

What camera is it? They must have a software update by now, no?

If not, you may be able to use Internet Explorer 11 with the cameras -- presumably DLink offers an ActiveX control for IE.

You might also try out:

http://portableapps.com/apps/internet/firefox_portable Mozilla Firefox, Portable Edition

https://portableapps.com/apps/internet/firefox-portable-esr Mozilla Firefox ESR, Portable Edition

A fully functional package of Firefox optimized for use on a USB key drive. A specialized launcher will allow most favorite extensions to work as you switch computers.

Firefox Portable is a 3rd-party build. Support is available here: http://portableapps.com/forums/support/firefox_portable

You can use sync to share data between profiles. But some data cannot be shared between different versions.