Google's AppCompat v21 brings Material Design to pre-Lollipop devices

This is great news for developers. Google has updated the popular AppCompat library to version 21, and introduced a new Toolbar widget that will allow for a more Material Design look and feel in apps built for devices running older firmware. This update is exactly what we're all seeing in recent updates for Google Apps like the Play Store or Play Newsstand, and is how we can have the new design language on the majority of Androids, even if they aren't running Lollipop.

source: androidcentral