I think the update was due to models that have the cellular data radios.Interesting that iOS is shown as updated for the iPad Mini (1st Gen) from 9.3.5 to 9.3.6 but the iPod Touch 5th Gen is not included in that same upgrade. Both are (were?) limited to iOS 9.3.5. I checked the both my iPod and my iPad Mini and it didn't show 9.3.6 as an available upgrade for either. I wonder if they have not been actually released yet.