Hello Linux Geeksters. As you may know, Firefox 37 has been released recently released, coming with a new user rating system that allows the users to easily send feedback to Mozilla, it now uses HTTPS for Bing searches, got support for CSS display:contents, disabled the insecure Transport Layer Security (TLS) versions for security reasons, includes better support for HTTP/2, extends SSL error reporting, and supports e-mail name constraints in certificates, among others.

Recently, Firefox 37 has been added to the default repositories of all the supported Ubuntu systems.
To install Firefox 37 on Ubuntu 15.04 Vivid Vervet, Ubuntu 14.10 Utopic Unicorn, Ubuntu 14.04 Trusty Tahr, Ubuntu 12.04 Precise Pangolin, Linux Mint 17.1 Rebecca, Linux Mint 17 Qiana, Linux Mint 13 Maya, Pinguy OS 14.04, Elementary OS 0.3 Freya, Elementary OS 0.2 Luna, Deepin 2014, Peppermint Five, LXLE 14.04, Linux Lite 2 and other Ubuntu derivative systems, all you have to do is update the local repository index and install the firefox package. Like this:
$ sudo apt-get update
$ sudo apt-get install firefox