Google started rolling out its screen mirroring feature for Chromecast earlier this year. Back then, only a few devices were supported but it now works on any phone or tablet with Android 4.4.2 or newer. A new “guest mode” has also been added. 

For everyone with Android 4.4.2
You can now use Chromecast’s screen mirroring feature no matter if there is a Sony, HTC, Motorola, Samsung or LG logo on your phone. The feature is still in beta but now works on any device running Android 4.4.2 or later.


Screen mirroring is an easy way to share photos, video or other information with your family or friends on the biggest screen in the living room. You can activate the mirroring functionality in the Chromecast app on your phone. How well it works depends on your phone and on your home WiFi network.

The update comes ahead of the Android TV roll-out in 2015. Android TV is Google’s new TV platform for Smart TVs and media boxes, and it already has Chromecast built in, giving you the option to either use the apps or games from the Android TV interface with a remote control or “cast” content from your phone or tablet.
 
The update also adds a new "Guest Mode" on Chromecast that lets guests use your Chromecast even when they are not connected to your home WiFi. Google is using a "WiFi beacon" method to identify people sitting in your living room.