Update adds new features to Android version of WhatsApp
Other new capabilities include an improved method that enables you to quickly start, mute and delete multiple chats. Each chat can now be easily identified by the solid color that you assign to it, and a new Quick Camera button pops up in chats, allowing you to choose a picture or video from your camera roll.
The update should be available from the Google Play Store by now. You can check it out by opening the Play Store app, tapping on the hamburger menu on the left, and clicking on My apps. Scroll down to WhatsApp to see if the latest version has been bestowed upon you. And if you don't yet have the app on your phone, you can download and install it now, assuming that your device is running on Android 2.1 or higher.
source: WhatsApp (Android|iOS|Windows) via SlashGear