Opera 10.50 earned another public pre-alpha version, but this one is for Windows users only so far.

Originally announced in December, the significantly faster preview build of what's to come for the browser doesn't introduce any major new features, but it does include several important bug fixes from the last pre-alpha build.

Opera 10.5 pre-alpha 3172 introduced Windows 7 support and a slight redesign, along with a rocketing new JavaScript engine. (Credit: Screenshot by Seth Rosenblatt/CNET)

Included in Opera 10.50 pre-alpha 3199 are upgrades to the new core rendering engine, which looks in preliminary testing to bring Opera's rendering speeds at least to parity with Google Chrome. Windows 7 integration and video support have been improved, while support for IMAP compress and context menu support for "inspect element" have been added. Several mail issues and other common crashes have also been addressed.

Mac and Linux versions of the new build haven't been released yet, and the publisher has pointed out two known major bugs: a lower score on the Acid3 rendering test than in Opera 10.10, and a Document Object Model, or DOM, regression. Opera expects both to be fixed by the next release. In the blog post announcing the new build, Opera also put out a public call for more bug reporting.