4. Using Wi-Fi and Bluetooth toggles in Control Center
Apple has changed the behavior of the Wi-Fi and Bluetooth toggles in iOS 11, which is confusing a lot of users. If you disable the Wi-Fi or Bluetooth toggle in Control Center, the iOS device will immediately disconnect from Wi-Fi networks and Bluetooth accessories, but they will continue to be available for what Apple calls important features such as AirDrop, AirPlay, Apple Pencil, Apple Watch, Continuity features like Handoff and Instant Hotpot and Location Services. So when you disable the Wi-Fi or Bluetooth toggle from the Control Center, the color of the icons change from blue to gray.
If you want to disable Wi-Fi and Bluetooth completely then you have to do it via the Settings app. If you’re getting confused then you can differentiate the 3 states visually.
Status: On – When Wi-Fi and Bluetooth are enabled, the icons are blue in color as seen below.
Status: Disconnected – When you disable the Wi-Fi or Bluetooth toggle in the Control Center, the color of the icons change from blue to grey as you can see below.
Status: Off – When Wi-Fi and Bluetooth are disabled from the Settings app, the color of the icons change from blue to grey, and they gain another indicator. A diagonal line through the icons to confirm that they are completely disabled as seen below.
So I hope this makes it a little easier to understand the behavior of the Wi-Fi and Bluetooth toggles in the Control Center in iOS 11.