I upgraded to 6.02 and still get this message from Gmail: "You are using an old version of Firefox which Gmail no longer supports. Some features may not work correctly. Upgrade to new version."
When I opened Gmail in my Firefox browser, I got a message I've never seen, before: "You are using an old version of Firefox which Gmail no longer supports. Some features may not work correctly. Upgrade to new version." I clicked on upgrade to a new version and was taken to the Mozilla site, where I downloaded the latest version of Firefox... then, when I restarted my computer, Gmail still gives me the same message!! What's going on?
You posted with a Firefox 3.5.5. user agent:
- Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:184.108.40.206) Gecko/20091102 Firefox/3.5.5 (.NET CLR 3.5.30729)
Had the same problem, reset your user agent, solved it, here's the how to: https://support.mozilla.com/en-US/kb/Websites+or+add-ons+incorrectly+report+incompatible+browser
I have another problem - Firefox no longer supports my Mac OSX so I can't download the latest Firefox. At least not without changing my operating system. Maybe that will be bad luck for Gmail...
Firefox 4 and later require at least OS X 10.5 and a Mac with an Intel processor.
For an unofficial Firefox ESR 10.0.4 compatible version (TenFourFox) that runs on PowerPC Macs with OS X 10.4.11 or OS X 10.5.8 you can look at:
Be aware that TenFourFox doesn't support plugins.