It looks like you are using a old package build of Firefox 88.0.1 and if there are no more Firefox updates in the package manager then your version of Mint is likely EOL is packages support.urrent version of Firefox. You can update your Linux Mint to a currently supported version to use the package builds of Firefox from Mint or you can use the Linux tarball version from Mozilla. https://www.mozilla.org/firefox/all/ There is no package, installer or setup as it is basically an archive. You extract and run the firefox script or firefox-bin in the Firefox folder to start Firefox is the basics. You need to make sure this Firefox folder has read/write permissions for the user to get internal Firefox updates from Mozilla. If you are the only user then placing the Firefox folder in Home is a easy way. There is Firefox icons in the firefox/browser/chrome/icons/default/ folder you can use for the desktop launcher shortcut.