Update software without using WiFi

No, you can't. Wifi connections are required either updating wirelessly, or via iTunes on a computer (which must be connected to wifi network).

It's not only a matter of downloading, but also of verifying the update with Apple servers.

Regards

Giulio

The computer doesn't need to be connected via WiFi, it can be connected to the Internet via an Ethernet cable.

Correct, the computer needs to have Internet access, it doesn't matter how.

Giulio

You are quite welcome :-)

Giulio