I’m testing the iOS public beta 11.4 and have seen a significant drop in data usage. One thing, however, is I’ve noticed, in general, that apps that are allowed to run as a background process, seems to do more now than before, even on earlier devices. I believe it may be app specific, using data at will. I completely removed all non apple apps prior to installing the iOS beta 11.4 and did notice almost zero data use. I believe third party apps may need tweeeking for iOS 11.x to help eliminate excess data use. My iPad actually was doing the same, however, since it’s on WiFi, I never noticed. It wasn’t until I installed a network monitor on my home network, that I noticed this issue.
I’ve since restored all my apps with iOS 11.4, and see the issue still exists, just not to the degree I was before. Disabling cellular for apps I don’t use outside of home and disabling background app refresh has not only eliminated the data “leaks” but significantly increased my battery life.
If you’re having this data usage issue, go into settings, then Cellular, then look at your installed apps. It will show their cellular data usage under each app. I had a couple of games using 500Mb to 1Gb, and I haves even OPENED them since installing. Turn data off for any app you don’t use on cellular! If you mistakenly turned data off for an app you use, no worries, when you open it, it will TELL you it needs WiFi or cellular data to function and gives you a button to go right into settings to turn data back on. I think, because many people have unlimited data, app devs are taking advantage of this by having their apps constantly connect, for updates, or promos; whatever. I think we’re noticing this with the iPhone X because it’s shiny and new as I’ve seen this data use issue with others with iPhone 8 Plus down to iPhone 5’s. But everyone I know with these devices don’t notice it due to unlimited plans and many being grandfathered into unlimited data plans that cannot be throttled.
I did put my SIM card into an android phone, an LG Phoenix 2 with Nougat on it and experienced the same data use from the android versions of the same games and apps. Office was a huge offender as was several games like Injustice 1 & 2, most Marvel fighing games, and work out apps! So it’s clearly NOT an Apple only issue as I though, but a very gratuitous “open gate”, if you will, for app devs to use cellular data whenever they want, regardless of the amount of data.
I DO fault Apple here. There is NO REASON what so ever for them not to give us the ability to set warning levels and our own data caps like Android has hand pretty much since it’s inception.
I hope this helps folks out.