Websites say that Firefox is outdated or incompatible even though it's the latest version https://support.mozilla.org/en-US/kb/how-reset-default-user-agent-firefox You can check out at the browserspy website how websites see you: http://browserspy.dk/browser.php http://browserspy.dk/headers.php +++++++++++++++++++++++++++++++++++++++++++++++++ https://support.mozilla.org/en-US/kb/how-reset-default-user-agent-firefox http://www.howtogeek.com/113439/how-to-change-your-browsers-user-agent-without-installing-any-extensions/ Do you have enabled "Resist Fingerprinting" if you check ‘’’Resist Fingerprinting’’’ on the ‘’’about:config’’’ page as this affects the user agent? *privacy.resistFingerprinting = false *https://support.mozilla.org/en-US/kb/firefox-protection-against-fingerprinting