That’s right, Firefox 78 is an ESR (Extended Support Release), which is perfect for enterprises that want to provide their users with a very stable and well-tested Firefox release. ESR branches are usually supported for 12 months. It replaces the Firefox 68.0 ESR series. This means that GNU/Linux distributions shipping Firefox ESR, such as Debian GNU/Linux, can now upgrade to the latest 78.0 ESR version to offer their users a newer Firefox release with modern features. Talking about modern features, Firefox 78 introduces new minimal system requirements for Linux systems. Therefore, to install Firefox 78, your distro must ship with GTK 3.14, GNU C Library (glibc) 2.17 and libstdc++ 4.8.1 or newer versions.