message.json:
{
"version": "1", // only for internal, never touch this
"mustHavePersonalRadio": 1, // player must have a personal radio to open message menu
"radioMustHaveBattery": 1, // player must have a working battery in personal radio to open message menu
"showOnlinePlayersInMessageMenu": 0 // message menu shows online players, player can add from there the contact. Player can always exchange contact by an F action when they meet.
}