Software update

You don’t need to be logged in to your Apple ID to update iOS, but you do need to be for app updates.

To update all of these requirements must be met:

• You must be connected to a Wi-Fi network (and not a personal hotspot)
• The phone must be charged to at least 50%, and preferably plugged in so it stays above 50% during the update
• The phone must not be in Low Power Mode
• The phone must not be connected through VPN
• The phone cannot be in Airplane mode

iCloud has nothing to do with upgrading your device. You need to be signed into the iTunes & App Store, but you do not need to be signed into iCloud. You also need Wifi if you are going to upgrade OTA. Otherwise, you can hook your device up to a computer that is running iTunes, and update it from there.