The app is very simple and uncomplicated, so it's easy to use. It would be better if there were some improvements. 1. On the chat screen, regardless of how long the automatic message deletion time is, I hope it will be arranged as the person who sent and received the most recent message. 2. Sometimes a message cannot be deleted after the set time. 3. I hope there is a function that fixes the person you want to the top in the chat window. 4. The call is often out of reach. It needs to be improved. I really like the app. We look forward to your continued updates.