Thanks for reporting a fake update. Please see the article I found a fake Firefox update.

. Whenever you get a message / popup that software / files need to be updated;

DO NOT USE ANY OF THE PROVIDED LINKS

While this may be a legitimate message, it could also be Malware or a Virus. Anytime you want or need to check for upgrades, go to the website of the True Owner of the program in question. For example, to check out Firefox, go to https://www.mozilla.org {web link}

You can report such a site at; Google Report Phishing Page {web link} which is the same when done while on site by going to Help > Report Web Forgery

Help us safeguard Mozilla’s trademarks by reporting misuse {web link}

For the last eight months, an epidemic of Fake Update Notices have been popping up all over the place. https://support.mozilla.org/en-US/kb/i-found-fake-firefox-update

maxx_4 said

How does one make sure a download is from you/firefox? just received an urgent download. although am very leery of hackers, as have been before.

Keep it simple, the updates are always done internally in Firefox and Firefox downloads for Windows, Mac OSX, and Linux will always be from a Mozilla page like www.mozilla.org or www.mozilla.org/firefox/all/