Hello Linux Geeksters. As you know, Opera is a popular web browser, available for Linux, Mac OS X and Windows. Last year, Opera has adopted Google’s forked WebKit engine, the new versions of the browser being based on Chromium. After the release of Opera 12.16, the Linux support has been dropped, until Opera 24 Dev has been released for Linux, Windows and Mac OS X.

The latest version available is Opera 25 Dev, available only for 64 bit Debian/Ubuntu systems. While it has been specially developed to work on Unity and Gnome Shell, it can be most likely used on other desktop environments. On Linux, it now officially supports web notifications, via some special pop-ups and many bug-fixes have been implemented. For more information, read both the announcement and the changelog.
In this article I will show you how to install and test Opera 25 on 64 bit versions of Ubuntu 14.04 Trusty Tahr and derivative systems: Linux Mint 17 Qiana, Pinguy OS 14.04, Elementary OS 0.3 Freya, Deepin 2014, Peppermint Five, Linux Lite 2.0, LXLE 14.04 and other Ubuntu 14.04 derivatives.
Because the developer branch of Opera is not available via any repository, we have to download the Opera 25 deb package from the Opera pool and install it via command-line. I prefer gdebi over dpkg, due to the fact that it also handles dependencies.
How to install Opera 25 on 64 bit Ubuntu 14.04 systems, using Unity or Gnome Shell:
$ sudo apt-get install gdebi
$ wget get.geo.opera.com/pub/opera-developer/25.0.1583.1/linux/opera-developer_25.0.1583.1_amd64.deb
$ sudo gdebi opera-developer_25.0.1583.1_amd64.deb
Because the Opera 24 deb package gets updated frequently, most likely version 25 will be replaced by a new one soon, so when this link becomes obsolete, download the deb for amd64 Ubuntu systems from HERE and install it via gdebi.
Optional, to remove opera, do:
$ sudo apt-get remove opera