You may have seen recent news regarding the compromise of several U.S. telecommunication providers by “Salt Typhoon,” threat actors operating out of the People's Republic of China (PRC). The U.S. Cybersecurity & Infrastructure Agency and the FBI have advised all Americans to discontinue the use of SMS and RCS based texting and instead use end-to-end encryption solutions like Signal, or WhatsApp. The issue is specific to cross-platform texting (i.e. Apple to Android). Android to Android or iPhone to iPhone text messaging is secure, but messaging from one operating system to the other can pose security risks due to the limitations of their end-to-end encryption.
U.S. government officials believe that these threat actors still have access to telecom networks, so there is an ongoing risk of communications being compromised. Voice communications are also affected. Fully encrypted communications are the best defense against this threat.
It is recommended to follow National Security Agency (NSA) guidance on Mobile Device Best Practices.