The app is not the issue. If your in an area without internet connection then you cant respon to texts from clients that may be time sensitive. Airbnb needs to reinstate its contracts with carriers for messaging.
I've finally , after three attempt, gotten an answer regarding the new SMS issue. An agent told me that AirBNB ended the SMS texting feature this summer. No reason given. This is a problem if were not in an internet connection zone.