I'm pretty sure this is new and isn't even up on the site yet but you can check for updates via Settings/Device/Software Update
Mine just upgraded after I did a factory reset to 13.3.0.5 the old one was 13.3.0.2.
No release notes yet.
My UI is black again well very very dark grey!

Before it was charcoal grey at even the lowest brightness.
As of 11/04 the new firmware is live!
http://www.amazon.com/gp/help/custom...deId=201357190
This is a bug fix release so be sure to update!