Apple released iOS / iPadOS 13.6 this week. The main innovations are the Car Key app, which turns the smartphone into a car key on iPhone XR and newer (except for the new iPhone SE). In the Health app, you can now keep a symptom diary that can be conveniently shown to your doctor.
You also have more freedom with regard to auto-updates: you can configure whether a smartphone or a tablet automatically install and install new OS versions, or just download and wait until you decide update. Of course, you can turn off auto-update completely - and you might want to, because updating to iOS 13.6 turns on this feature automatically, regardless of the previous settings.
How to disable automatic download and installation
To do this, in the settings, open "General" → "Software update" → "Configure auto-updates". Here you will see two radio buttons that are responsible for downloading and installing updates. You can disable the installation item and leave only automatic loading, or disable both functions.