Google is making some big changes to Android for its so-called “L release” this fall, and starting today, it’s giving interested developers the chance to take an early look at it. There are three major changes on the surface of Android’s L preview worth paying attention to: an overall design overhaul, improved notifications, and rethought multitasking. KitKat’s sleek Holo theme is being replaced with a colorful new style called Material Design, which Google says is based on basic shapes and sheets of paper. Because Android’s L release is still in development, those design changes haven’t come to every corner of the operating system yet.