The second release candidate for WordPress 3.9 is now available for testing.
If you haven’t tested 3.9 yet, you’re running out of time! We made about five dozen changes since the first release candidate, and those changes are all helpfully summarized in our weekly post on the development blog. Probably the biggest fixes are to live widget previews and the new theme browser, along with some extra TinyMCE compatibility and some RTL fixes.
Plugin authors: Could you test your plugins against 3.9, and if they’re compatible, make sure they are marked as tested up to 3.9? It only takes a few minutes and this really helps make launch easier. Be sure to follow along the core development blog; we’ve been posting notes for developers for 3.9. (For example: HTML5, symlinks, MySQL, Plupload.)
To test WordPress 3.9 RC2, try the WordPress Beta Tester plugin (you'll want "bleeding edge nightlies"). Or you can download the release candidate here (zip). If you'd like to learn more about what's new in WordPress 3.9, visit the nearly complete About screen in your dashboard ( ? About in the toolbar) and also check out the Beta 1 post.
This is for testing,
so not recommended for