It's the developer preview but everything seems fine. If it does change I don't think it's to fix anything that's easily noticeable. I'm not lying when I say everything is better. I thought the phone app for KK sucked, having to hit the all contacts button and shit was annoying when it was at the top of the screen and buttons for recents and the dialer was at the bottom, plus the all contacts button didn't match shit, it's like they forgot about it and just stuck it somewhere. Everything is in a quick tab style menu at the top, way more user friendly and sleek looking now. I think the pull down menu is my favorite aesthetic change. It's just clean looking, and the animations are neat. Everything just looks better. This is my favorite Android release in a while.