I can see that iTunes and App Store has in Settings to not automatically download updates.
But what about iOS updates themselves? The recent iOS 11.3 update for example, is near 800MB, and when I use my main phone as a hotspot, then will my other iPhone silently download the iOS update?
The issue is important because the 800MB can cost up to US$12 at $15 per GB such as on Verizon, meaning that to download the update from iOS 11.2.6 to 11.3, it can cost me $12, and if 2 secondary phones, that means US$24 for downloading an update I wasn't aware of.
Best Answer
In short, yes. This is how it works:
There are a range of settings within iOS settings that you can use to manage what (incl. individual apps) have access to your cellular/mobile data connection, but these settings will not recognise a Personal Hotspot as anything other than another internet connection.