If you want to use the Atom publishing protocol, you now need to install a plugin in WordPress 3.5 because it has been removed from the core. Of course, the WordPress developers didn't bother to include a corrected version of the Atom Publishing Protocol server in the plugin; it still contains the over 2-year-old bug with media uploads. Fortunately, my patch still works, but now it needs to be applied to a different file. Quite a mess, what they're doing there. And when I see how the bug in the WordPress core was ignored, my hope that someone will take the trouble to fix the plugin is pretty close to zero.