FamilyApp provides private keys to encrypt (lock) each of your chats, allowing only those included in the message (those who have the keys) to see what's going on! But what happens if you get a new device? Don’t worry; you can transfer the keys to your chats to the new device.
Start by opening FamilyApp on both your old device and new device. When you log into FamilyApp on a new device, tap the prompt, “Move keys to new device.” Then tap “generate QR Code on the new device.” Scan that QR code with your old device, and you should receive the message that you have a successful key transfer onto your new device.
Don't have your old phone? Not to worry! You can generate a new private key, and your family members will decrypt old messages for you.