The latest Opera 12.10 snapshot, intended for enthusiasts and developers, is here, the next small step towards the stable Opera 12.10 release. Beta versions of Opera 12.10 are already available.
This latest release fixes several bugs and addresses several issues that have plagued users for some time now.
But the interesting addition is code to enable Opera to test which connection is faster, either via IPv4 or IPv6, and then use that protocol for the remainder of the session.
This works, obviously, if your ISP offers IPv6 connections (unlikely), if your computer is configured to use IPv6 to connect to the web (also unlikely) and if the website you're connecting too offers IPv6 connectivity by default, a dual stack, (very few do).
But if you're one of the three Opera users that meets the criteria, congratulations, Opera will now choose whichever connection is faster, leading to measurable but probably unnoticeable speed improvements.