tfoil2

Yes, turning Background App Refresh off goes a long way toward achieving this (and saving battery). Even with Background App Refresh turned off though, some activities may continue, particularly Location, audio, voice, and the like [https://developer.apple.com/library/content/documentation/iP...]. This is why it's Location "While Using" is important. It also looks from OP's comment [https://news.ycombinator.com/item?id=14502423] that (some of?) these features will be more prominently displayed to users. This is good, users should have complete knowledge and control of their devices, particularly as it affects privacy.

In iOS 10 Settings > Privacy > Location, under the "Location Services & Privacy link, it says: "Your iPhone will keep track of places you have recently been, as well as how often and when you visited them, in order to learn places that are significant to you. This data is kept solely on your device and will not be sent to Apple without your consent. It will be used to provide you with personalized services, such as predictive traffic routing." This is consistent with Apple's philosophy of keeping personal data processing on-device as much as possible to protect user privacy. You can always keep the frequent locations feature turned off, or use "Clear History..."

Right, but this is at developer discretion. I always want to see user-level control for privacy-enhancing features.

Yes, upgrades are always free, and new iOS versions are typically supported on several generations of older devices.

Next battle: getting Apple to give users more granular Location controls. Almost NO App really needs precise GPS. "within a mile" or city or zip code or other fuzzier locations should be fine for most apps. Users should have a better trade-off than exact or nothing.

Screw any app that really thinks it needs my precise coordinates in the foreground, let alone the background. Turn-by-turn directions in maps is the only exception I've found in 10 years of iPhone use.

I see the reference to the "1998 ACM Subject Classification", but this paper is part of a May 2015 conference: http://www.cs.ucla.edu/~todd/research/pub.php?id=snapl15

So Alice quits programming and goes back to cooking because Math is Hard. And we wonder why there are gender issues in tech.