Your Firefox reported itself to be Firefox 43, so I have to wonder, "what updates?"

If something is holding you back from upgrading to Firefox 55 (or Firefox 52 ESR if you prefer the Extended Support Release), please let us know so we can suggest solutions or workarounds. Version 43 is not secure; Mozilla discloses security flaws after each new release.

Sometimes Firefox reports the wrong version because that information was saved in a preferences file. You can check using the steps in this article: How to reset the default user agent on Firefox.

And see: http://kb.mozillazine.org/Locking_preferences

You can use the mozilla.cfg file in the Firefox program folder to set or lock preferences and run privileged JavaScript code.

The mozilla.cfg file needs to be in the main Firefox program folder.

These functions can be used in the mozilla.cfg file:

defaultPref();	// set new default value
pref();	// set pref, allow changes in current session
lockPref();	// lock pref, disallow changes

This requires a local-settings.js file in the "defaults/pref" folder where the channel-prefs.js file is located that specifies to use mozilla.cfg.

pref("general.config.filename", "mozilla.cfg");
pref("general.config.obscure_value", 0);

The mozilla.cfg file and possibly local-settings.js need to start with a comment line (//).

See Configuration:

• https://developer.mozilla.org/en-US/Firefox/Enterprise_deployment

See also:

• http://kb.mozillazine.org/Locking_preferences
• http://mike.kaply.com/2012/03/16/customizing-firefox-autoconfig-files/