I will be traveling in Bolivia with travelpass. Want to be able to receive calls from home at any time (or most of the time), including where no wi-fi. So I would have to leave phone OUT of airplane mode. I don't mind incurring the $10 daily charge but do not want to incur additional roaming/ data charges for app updates or whatever else goes on in the background. This has happened to me on previous trips. How to avoid? What specifically should be turned off? This is an iphone SE.