I've wanted a whitelist only setting for a very long time... and I have also resorted to using the iPhones DND feature but instead of favorites I just use conta

I've wanted a whitelist only setting for a very long time... and I have also resorted to using the iPhones DND feature but instead of favorites I just use contacts. Havn't heard from the fake CRA, chinese immigration or duct cleaners for ages... I do still get text messages so I'm not sure what people are talking about by 'all or nothing' ... As far as I can tell, the only downside is anyone in my contact list can wake me up at 4am...