A new Opera 31 build has been promoted to the Beta channel and it brings interesting changes.
Opera 31 Beta (31.0.1889.16) has been recently released, bringing a redesigned Discover feature, the Language and country settings have been moved under the Settings option, some under the hood optimizations to speed up the browser have been implemented, and libnotify notifications have been added, among others.
Installation instructions:
To install and test Opera Beta on Ubuntu 15.04 Vivid Vervet, Ubuntu 14.10 Utopic Unicorn, Ubuntu 14.04 Trusty Tahr and derivative systems, like: Linux Mint 17.2 Rafaela, Linux Mint 17.1 Rebecca, Linux Mint 17 Qiana, Pinguy OS 14.04, Elementary OS 0.3, Deepin 2014, Peppermint Five, LXLE 14.04 and Linux Lite 2, you need to download the deb package and install it via command-line.
For now, Opera Beta is available as 64 bit packages only, but 32 packages should be created starting with the future Opera releases.
How to install Opera Beta on 64 bit Ubuntu and derivatives:
$ sudo apt-get install libnotify-bin gdebi
$ wget http://deb.opera.com/opera/pool/non-free/o/opera-beta/opera-beta_31.0.1889.16_amd64.deb -O opera-beta_amd64.deb
$ sudo gdebi opera-beta_amd64.deb
Because the Opera package gets updated frequently, download the deb for amd64 Ubuntu systems from HERE and install it via gdebi.
Optional, to remove opera-beta, do:
$ sudo apt-get remove opera-beta