A Reuters photographer captured a photo of Mike Waltz, a former National Security Advisor, using an unofficial version of the Signal app called TM SGNL. The app is designed to archive messages and is likely violating Signal's open source license. The company behind TM SGNL, TeleMessage, has executives with ties to the Israeli Defense Forces' Intelligence unit. The app is not publicly available and can only be installed on devices enrolled in a managed service.