Hello, please can someone advise how to update firefox on the Linux users laptop, as Netflix said i need to update before i can use the app. Thank you.

https://support.mozilla.org/en-US/kb/update-firefox-latest-release

If you are using the Firefox tarball from Mozilla then it has internal updates like the macOS and Windows versions has. You just need to make sure the Firefox folder has read/write permissions for the user to get updates. A easy way is to have the Firefox folder in Home. https://support.mozilla.org/en-US/kb/install-firefox-linux

If you are using a package build of Firefox from your Linux distro package manager. If there are no more Firefox updates then your version of Linux distro may be EOL in software package updates. In this case you need to update your Linux distro to a current support version or use the Linux tarball from Mozilla.