With iOS 15.4, it is possible to download updates for your iPhone or iPad in 4G and no longer necessarily in Wi-Fi. It was already possible to do so in 5G before.
iOS updates are downloaded in 4G if necessary since iOS 15.4
Beta 3 of iOS 15.4, available since yesterday, displays a pop-up allowing you to download updates in 4G. “Use cellular data for downloading?” If you disconnect from the Wi-Fi network, you can continue downloading using your cellular data. This will generate an additional cost”, says Apple. The mention of “additional cost” is however to be put into perspective, it should be understood that this will consume your Internet quota.
It is true that you still have to be careful because the new betas generally weigh several hundred MB. There is talk of several GB for large iOS updates. This can therefore have a noticeable impact on your monthly internet quota. But in France, we have packages with several tens of GB, or even more. At the moment, SFR RED offers 100 GB for €10/month or 200 GB for €12/month. So downloading updates over a cellular connection shouldn’t pose much of a problem.
Going back to the iOS 15.4 message, there are two options available: “Use Cellular Data” and “Don’t Use Cellular Data”. It’s up to you to choose what you prefer. If you choose the second option, then downloading iOS updates will still require a Wi-Fi connection.
It is worth noting that Apple has decided to take precautions, since users will each time have to confirm whether or not they are using the cellular network to download an iOS update. We can thus accept to download in 4G a particular update then want the others in Wi-Fi.