Google has updated the beta channel of Chrome OS to version 21.0.1180.50. This version is available for Chromebooks (Samsung Series 5, Samsung Series 5 550, and Cr-48) and Samsung Chromebox Series 3.
The release brings major UI improvements. Google has re-designed the App list to work alongside browser and apps. There is now a new connection manager to manage your connections. One of the most notable improvements is the introduction of new print UI. Now, you can also select your own custom wallpaper.
In addition to that there are regular security fixes. However, if you are running this channel keep in mind that it is not intended for production use. There are two major bugs in this release so if you are not an enthusiast you may want to stay with stable channel. Two major bugs of this release are - connecting to hidden networks fails when you try to connect to it for the first time and it can't enable mobile data for locked SIM on y3300 and y3400 modems.