According to the official news, WordPress 4.1 will potentially drop on Tuesday. The most interesting changes are TwentyFifteen and the WP_Meta_Query optimizations which will help plugins that rely heavily on postmeta. A full list here.
To play critic for a moment. I’m not sure I like the new default theme. Not that I dislike it either. But I don’t have the oooohhhhh feeling I’ve had in previous years. Maybe thats because from the screenshots it doesn’t look much different than several themes already available. But maybe once I demo it’ll feel different.