WhatsApp has always allowed you to add a voice note to a conversation, however, this option has generally been buried inside a menu. Now with BBM going cross-platform, WhatsApp is making sure it changes a few things to retain its number one position with 300 million users. One such change is bringing the voice note icon right where you type your message.
This “feature” does not an updating of the app and should automatically start showing up as when it is rolled across devices. Supported phones include iPhone, BlackBerry as well as Windows Phone 8 and Android based devices.