Why is Software Updates on my iPhone using so much data?

FWIW I had the same issue pop up this month--341 mb "Software Updates" in cellular data usage, plus another 320 for other system services, which is a dramatic increase. But I was never asked to update/choose cellular or wifi. I have cellular data usage turned off for app store, have Data Mode as Standard and had Automatic Updates for iOS turned on. I've now switched the latter off. We'll see.

Because Software Updates are very large so you use a lot of data. When updating, make sure the iPhone is connected to Wi-Fi. and if asked wether to use Cellular data or Wi-Fi choose Wi-Fi.

iOS 16 now offers the option to use Cellular data for updates, but you are free to use Wi-Fi by choosing the option when asked.

For what it’s worth I’ve had the most relief by selecting “low data mode” in Settings>Cellular>cellular data options>data mode.

good luck

This alone was the cure for me. Select Low Data Mode In Cellular Data Options.

I found out that when I switch off 5G (and use LTE instead) has fixed the problem (so far). Could someone test this theory too?

I have a theory that the new Apple Map is the cause. Try turning off cell use of your Apple map, and see if your “software update” is still consuming a lot of data, if any.

I am from Canada travelling in the US and have the same problem. I am 1.3 GB in software updates with everything turned off. Spent over an hour on the phone with apple support. No help or explanation was provided. I just want apple to stop pushing updates to my phone over cell but can’t seem to do this.

Update: turned off “automatic updates” 3 days ago. System settings data usage nearly doubled since then, with another 400 mb for Software Updates. I will switch to “low data usage” now. Outrageous that setting changes do not reduce this activity.

I also have all cellular data turned off and have still used over 750 MB of cellular data for Software Updates in the first three weeks of September. I don't think that I had the problem before updating to 16.5.1. Now running 16.6.1 and am hesitant to update to iOS 17.

From the number of people on this page with the same problem, it seems Apple has a problem they are not addressing.

I’m experiencing the same problem. It happened on iOS 17.2.1 with all automatic updates and app refreshes switched off, even low-data-mode and low power mode switched on. Consumer 8GB through System Services —> Software Updates within three weeks. Than updates to iOS 17.3 and for almost two weeks I thought it had been fixed. However, within two days another 2GB were eaten. This happens within minutes of not been connected to WiFi. It’s a serious iOS bug!!! (iPhone XS, no 5G)

Does “everything turned off” include Cellular Data in Settings/App Store:

I've had the same problem, but with App Store Cellular Data turned off. Still looking for an answer. I'm trying with Automatic Updates for iOS turned off. It's unclear whether iOS updates require approval prior to download--Apple Support reports that users are prompted to choose, in iOS16, whether to download over 5G or wait for wifi. I was not prompted thusly. I'm unsure if the 660mb spike of system services data usage—half of which was Software Updates—actually included an iOS update. But the spike came out of nowhere and killed my data allowance.