Firefox never asks for a cell phone number or any number to upgrade. Are you maybe seeing this request from gmail, or Facebook, or some other website? Some websites do request a cell phone number as a security measure, in the case that you forget your password they can send you a text with a security code to prove your identity. These programs are completely voluntary however, and you don't have to participate in them.

But, if that is the case, it has nothing to do with Firefox (Mozilla never asks for phone numbers), and you can always take issue up with the website you are getting this mesage on.

If this isn't on a website, let me know where you are getting the message and maybe we can narrow it down for you.

Firefox doesn't ask for your cell phone number to upgrade Firefox. You may have seen a fraudulent form displayed by a phishing site or a malware distribution site, or you may have malware on your computer.

You might want to run some supplemental security scans. These two tools are highly regarded:

Malwarebytes Anti-malware : http://www.malwarebytes.org/products/malwarebytes_free

SUPERAntiSpyware : http://www.superantispyware.com/

Also, if you can identify the sites you visited before receiving the update notification (try History > Show All History) you could report any suspicious ones here.

to TYLER You are wrong in your response to me. I opened a new user account on my windows computer. Then opened Firefox,which is already installed on my computer. To help my G/F get ready to do her unemployment. firefox home page came up and said I need to upgrade to the newest version. Ok fine, I clicked the link to upgrade. There is NO history or past websites to deal with. BTW I am NOT a novice, and this was NOT a phishing scam from some other site. IT DEMANDED MY CELL PHONE NUMBER TO DO THE UPGRADE. NO CELL PHONE NUMBER, NO UPGRADE. I WILL NOT GIVE OUT THAT INFO! MOZILLA NEEDS TO REMOVE THAT DEMAND.

And there is NO Malware on that system. It is a CLEAN system rarely used and almost never on the internet. I always use my Linux computer which is so much more secure than windows will ever be.

When you started Firefox, did it come up with your customizations or a completely new profile?

Is the home page about:home, or another page such as a page on google.com?

Can you post a screen shot of the message you see about upgrading?

To bypass the "upgrade" process, you could install Firefox 11 from the full installer: http://www.mozilla.org/en-US/firefox/fx/

If you don't already have a backup of your Firefox profile data, that would be a good idea before a major version leap. See Backing up your information. (You can copy your entire Firefox profile folder somewhere outside of the Mozilla folder.)

cc1950, I'm guessing you must be seeing this request from somewhere other than a Mozilla website, there is no website that requests a cell-phone, or any sort of phone number. Now, some pages do offer the option to give your email address to be notified of updates, but never a phone number.

As asked above, I think a screenshot would help clear this up really quick :)

Well I won't be in a position to do the screen shot for several days. I don't use that system very often and I am involved in more important matters. I'll get to it when I can. But I know what I saw on screen. as above. Created a new user account on win 7. Opened the account clicked on the firefox browser icon, and up came the the screen. I tried a fake cell phone number. It wouldn't accept it. Has to be a real number. So if it was a phish it came from Mozilla backdoor or such. The system is clean no bookmarks, no visited sites etc. Have three different anti virus / malware on the system that run automatically. And yes they are up to date.

• You are probably running a fake Firefox. Uninstall it from the Windows Control Panel and download it from mozilla.org/firefox then install it.
• Allow only one anti-virus protection and one protection against malware. If you have more, they annihilate between each other.
• See also Troubleshoot Firefox issues caused by malware.

It seems that many of your plugins are outdated. Check them using http://www.mozilla.org/plugincheck/.

Follow "scoobidiver's" advice and as part of the FF developer team, rest assured that a true Firefox application NEVER asks for phone numbers or any other sort of personal information of that nature.

It is not a fake version. And it ONLY comes up on a highly protected windows machine. Doesn't happen on my linux. so far I have not had time to do anything on that machine. Life has gotten in my way. When I get time to get back to it I will try a screen shot.

Well then you either have this coming from some other application (program installed on your PC or an extension) or some website that may be spoofing Firefox. If you search the Firefox source code for "cell phone" that doesn't even exist: http://mxr.mozilla.org/mozilla-central/search?string=cell+phone

Just a wild hunch. Did you by chance click on upgrade to Mobile For Android? Are you in any way syncing to your cell phone?