If I want to pay a friend or colleague via the app, does that person have to be a customer at my bank?

No, not at all. If you want to pay a friend or colleague via your contact list, remotely and using a mobile device, then that person needs to have the Payconiq by Bancontact app. If your friend is somewhere nearby and you want to make the payment by scanning a QR code with your smartphone, then your friend will also need to have the Payconiq by Bancontact app or some other banking app that has this function.