Can i change the POSITION_APP or TEXT_MESSAGE_APP json?

Hi again, i want to know if there is a way to change the message of these json? if is a way, how i can do it? and other thing this two apps are encrypted? i mean, when i send the message from a node to a gateway, all the route when the node send the message is encrypted, and when the gateway receive the data from the node the TEXT_MESSAGE_APP decode the message?
sorry for the question, but I really appreciate if someone can explain me this things :slight_smile: