Signal’s Android app will no longer support sending and receiving SMS messages. Those who currently use Signal as their default SMS app will receive notifications advising them to change. Your SMS messages will be exportable and importable into another app (as long as the other one supports that option).
Signal stated that it included SMS support in the first place to make it easier to use — you wouldn’t have to persuade friends to download the app before exchanging messages with them. While the change may be inconvenient for those who have relied on Signal for the majority of their messaging, the company has provided some practical reasons for the switch.
