Based on Conversations https://github.com/siacs/Conversations/
App permissions (in doubt, ask Anders S):
Identity - to be able to use the profile picture from the phone.
Contacts - to be able to use the profile picture from your contacts.
Photos/Media/Files - to be able to save / send photos and other files.
NFC - to be able to add friends in the app contact list with NFC.
Full network access - to be able to connect to QRTECHs chat server.
Prevent phone sleep - the app disables the wifi/3G/4G from entering low power mode (whichever is used) to be able to receive messages even when the phone is sleeping . This normally draws little power.
Run at startup - to be able to receive messages after the phone has started without manually opening the app.
Control vibration - to be able to vibrate for received messages.
View network connections - is used so that the app knows which network connection to use.