I'm on iPhone 5 and don't want to upgrade to ios 8 until at least the first or second update comes out. Woke up this morning to see that ios 8 decided to download automatically without me doing anything. So there it was sitting on my phone taking up an extra 2.6GB of space. I deleted it but don't want it to happen again. Is there a way to prevent this from happeing? I assume it has something to do with being plugged in and on WiFi while charging overnight?