You say you have Firefox 48.0 yet your Firefox useragent in your More System Details displays as Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:24.0) Gecko/20100101 Firefox/24.0

https://support.mozilla.org/en-US/kb/how-reset-default-user-agent-firefox

Also since you have Mac OSX 10.8 and not 10.9 or newer see https://support.mozilla.org/en-US/kb/firefox-osx for future.

I have a microsoft operating system

turkey123 said

I have a microsoft operating system

Well if you really are using a Windows OS then your useragent may need to be fixed as it is showing in your More System Details as if you have Firefox 24.0 on Mac OSX 10.8 Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:24.0) Gecko/20100101 Firefox/24.0

This may explain why websites are saying you need to update Firefox.

Again Please see https://support.mozilla.org/en-US/kb/how-reset-default-user-agent-firefox