Significant cellular data usage after IOS 8.4 upgrade (iPhone 5)

Won't restoring the phone update the software to 8.4.1, which also has issues?

Same issue here, in the last 10 days my cellular data usage went up considerably, almost going over my monthly quota. This happened even if I'm mostly connected via wifi.

Now, I'm trying to make a summary of various solutions I've read here and there:

* Restore the phone as new

* Disable Background app refreshing

* Disable updating apps via 3G

* Disable a number of system services using cellular data.

* Stop Apple Music

* Change SIM card

As buggy as iOS 8.4.1 can be, I think it's odd that disabling the three settings above are the real culprit. And restoring it as a new phone would surely impact all the people buying new phones, not?

The "big" changes I can think of, at least in my case, was the usage of Apple Music (even if mostly via wifi) and the fact that I traveled and had to change my SIM card. I'll try to get one replaced but in the meanwhile I'm monitoring the situation and see when there's a spike of data usage. Hopefully I'll see where the issue lies.

In the meanwhile I hope others are trying to do similar tests and see what happens.

What "issues?"

Have been monitoring mobile data usage for the past couple of days and the issue seems to be in system services time and location. It seems to be eating data and I'm not sure why. I have checked location services and the is no little arrow permanently on, however when I go into system services within this, there are lots of grey arrows. and am not sure how many of these settings need to be on and accessing my location.

HI, for the benefit of all I'm sharing this morning's grief in the hope that the massive data download caused by new Apple updates can be contained.

We woke up this morning to 20 email alerts from our provider to say we'd purchased $50 worth of excess data since 4.30am this morning.

We checked the info on the wifi modem to discover it had used 8G of data while we were asleep!

We normally have up to 3 Apple devices connected. At first we thought someone had hacked into our data, but the device doesn't have a long range.

We called our provider, but they couldn't work it out, however, very kindly refunded the data charge.

After 2 hours forensically checking all of our iPad settings, we discovered that after downloading the latest update, our iCloud settings caused the device to automatically back up all of the data on our ipads. This included all photos, videos, iBooks and accounted for the data use. We were completely powerless to prevent this, as it occurred when we were required to log in to iCloud to effect the update, and weren't aware that our settings had been changed.

My advice to everyone is once you've downloaded the update, turn off access to the wifi if you are on a limited plan, and check your iCloud settings before logging back on to your internet with the updated device.

When updating in future, we'll be more careful to check everything before touching the GO button!