Google updated the Hangouts app to version 2.1.075 yesterday 21st of April 2014. This is a big update with improvements for the Hangouts app for Android. Includes merged conversations with SMS, homescreen widget, simplified contact list.
The Hangout app for Android introduced with Nexus 5 and Android 4.4 KitKat and a replacement of Google Talk and the regular messaging app. You can use this app for SMS and Google text and video chat.
Download Google Hangouts 2.1
The app will work on any Android phone running Android 2.3 or up and is compatible with plenty of devices. The .apk size is 14.24 MB and the file name is com.google.android.talk_2.1.075 (1123407-30).apk. You can download Hangouts v2.1.075 .apk from this Media Fire mirror if you do not wish to wait for the update to be available in your device. Also, you can get it from the official source via this Google Play link.