Missing 2 GB of memory? I got an iPhone 4s 16 GB. I had around 3.5 GB free earlier today. Then suddenly the low memory message pops up. Nearly 2 GB is gone. I'm still on iOS 7. Haven't downloaded anything since I had cleared up that 3.5 GB. What happened? Did my iPhone autodownload an update or something? If so, how do I delete that update?
It sounds like the iOS 8 OTA update has downloaded. You can update to iOS 8 to remove the downloaded update package. Also see Remove OTA downloaded (but not installed) iOS 8