Opera 12 - the last major version of the browser to be based on the Presto engine - has received its final update. The main change in this release, is the inclusion of elliptic curve cryptography (ECC) cipher suites which are used for making secure connections between the browser and the site. Many domains have begun using ECC certificates which meant Opera 12 users couldn't connect, before this update.
With the 12.18 update, TLS RC4 is also disabled. This change was made in other browsers such as Firefox which switched off the cipher in late January. If you really need to enable the RC4 cipher, it is possible to turn it back on. The browser now supports TLS 1.2 by default.
Aside from Opera 12, the company's standalone mail client - Opera Mail - has also received a security update, after a researcher from Future Team alerted the browser maker to a vulnerability which may allow code execution on a user's machine using a carefully crafted message and some specific user interaction.
Opera is providing multiple ways to update to the latest versions of Opera 12 and Opera Mail. The first option is to just wait for an automatic update to be provided, otherwise you can download executables for offline installations (Download links: Opera 12.18, Opera Mail). As Opera 12.18 is going to be the last version of the browser supported on Windows XP SP1, the company is urging everyone to upgrade to a supported OS and switch to Opera 35.