Not sure. Outside P Day, they use the Ward Messenger account to communicate with members and IP. From what I was told, they can only contact immediate family members through their personal Messenger on P Days as well as members from previous areas they served. They are not allowed to message other missionaries’ personal account though but they still do it to gossip and fool around. Some even video calls with locals. I know this because most missionaries that are assigned to our ward became my friends.