In some earlier leaks we did see that Hangouts will replace SMS in Android 4.4 KitKat and this was confirmed with the launch of Nexus 5. After Google posted the factory image of Android 4.4, some apps have been extracted including the new Google Experience launcher and the Hangouts app too which does work on any Android 4.0+ device. The new version of Hangouts supports SMS integration, location sharing, moods, sharing GIF images and much more.
The Hangouts 2.0 update has not yet started rolling out but you can install the APK just as you would usually install but make sure the Unknown sources option has been checked in System>Security.
Since the APK is signed by Google, there should be no issues regarding any hack or tampering of the APK. Hit the download link below and install the app to experience the new Hangouts with SMS integration.
Download Hangouts 2.0 APK | MD5: 66941f97fcbe0a32cf9cb109cbd0bda1.
via Android Police