Update to use cellular data.
My phone has no service whenever it feels like cutting off. Then it says an update is needed to use data. And I have no idea how to fix it.
iPhone 7, iOS 14
This appear to be a Cellphone Carrier issue. To perform and update to iOS via Over the Air ( OTA ) method, you need a Stable Wifi Connection and plugged into charger. Then Settings >> General and Software Update and click in there to start the update process. Make sure there is enough Empty Space on the iPhone for the update to download, expand and install.