Signal downloads saw a significant spike in the US and Yemen after a government scandal in which high-ranking officials communicated sensitive plans via the app.
The Trump administration officials accidentally added a journalist to the group chat on Signal, allowing access to sensitive discussions, which were later published by The Atlantic.
Signal downloads on iOS and Google Play increased by 28% worldwide, with a 45% increase in the US and a 42% increase in Yemen after the scandal broke.
Signal, an encrypted messaging app, is designed for secure messaging and not intended as a secure repository for government military plans.