Hi   !

This is a fake   !

Firefox will always update from within the browser and not from a random webpage. Scammers have been using this tactic, trying to get users to download and infect their computer. Hard to get rid off, as they will change their URL on a daily basis. You could consider an ad-blocking add-on like :

https://addons.mozilla.org/en-US/firefox/addon/ublock-origin/?src=ss

Also see : https://support.mozilla.org/en-US/kb/i-found-fake-firefox-update

Also:

If you opened that patch file and your security software did not immediately stop it from running, your computer may be infected. Please try this tool to clean it, or consult the specialized forums listed in our malware support article.

https://www.malwarebytes.com/free/

Troubleshoot Firefox issues caused by malware

Finally, please be very skeptical of software update messages in websites. Saying you need to update your browser, or your video player, or your display drivers is a common way users are misled into installing malware.