Lacks of Info Is it end to end? Where is the server based and where the private keys are stored? Is the group chat encrypted? Can users clear the history of calls? Can users have pin number to access it? Can you close or log out? What protocols are used when it leaves the mobile? Sorry, I put 2 stars just to attract your kind attention and reply to these questions!
Very Professional with High Encryption Highly recommended for enhanced privacy. I can send messages that erase themselves!
Security improvement as per Google Advice
Minor Style Changes