Android users are from 22 May 2017 can not send more SMS via Hangouts Messenger allegedly. From March 27, Google wants to move the user via a message in the app to switch to another SMS app.
In a message that was posted on Reddit, Google announced the changes in Hangouts. Google Hangouts made in Android 4.4 KitKat at the preset SMS app.
In January 2016 Google then changed its strategy and began to extol Android Messages as a new app for SMS. Google also introduced to its developers conference I / O 2016, two new apps before: Allo for chatting, Duo for video conferencing. Thus Allo, Duo and Hangouts do not get in the way, Hangouts is converted into a messaging service for workgroups and teams, targeting business customers in the future. Analogous to Allo and Duo Hangouts is split into a chat app Hangouts chat and video conferencing app Hangouts Meet. How to continue with the current Hangouts app, is still unclear.