Google Chrome developers have released Chrome OS 19 for the users on the stable channel.
This is a major update which brings on the brand new user interface named Aura to Chromebooks.
Entirely redesigned UI and updated Window Manager
New modes for multiple monitor handling: mirrored (highest common resolution only), show only on primary, show only on secondary (Switch with Ctrl + F5)
New open source trackpad stack
Updated Scratchpad app
New file types supported
Functional and visual refresh of the Chrome OS Settings
Recovery tool supports re-formatting recovery media (use a previous recovery image USB)
Introduced new Japanese fonts (Motoya G04 Gothic/Mincho)
Google has also just launched their first Chromebox along with a new Chromebook in collaboration with Samsung.