Unbeknownst to many, the Bluetooth and Wi-Fi toggles in the Control Center in iOS 11 don’t do what you expect. Rather than completely disabling those features, they only partially disable Bluetooth and Wi-Fi. To clear up any confusion, Apple appears to have added explainer pop-up messages when either Bluetooth or Wi-Fi is toggled off, as first detailed in a report by MacRumors. The messages appear in the newest iOS 11.2 beta and they explain that both features will only be temporarily disabled when turned off from their Control Center toggles.
The first time a user turns off Bluetooth or Wi-Fi from the Control Center on their device, they’ll see a pop-up window that will say “disconnecting nearby Wi-Fi until tomorrow” or “disconnecting Bluetooth accessories until tomorrow.” The messages also explain that both Bluetooth and Wi-Fi are not totally disconnected in this case, however, they will still function to allow some features and devices to work with that iDevice. Bluetooth will still be available for the Apple Watch, Apple Pencil, Personal Hotspot, and Handoff, while Wi-Fi will still be on for AirDrop, Personal Hotspot, and location accuracy.
While the Control Center toggles turn off Bluetooth and Wi-Fi temporarily, there are a few cases detailed in an Apple support document that will turn both features back on automatically. Wi-Fi will turn back on when you connect to a Wi-Fi network via the Settings app; when you walk or drive to a new location; when it’s 5am local time; or when you restart your device. Bluetooth is similar: the feature will turn back on when you connect to a Bluetooth device via the Settings app; when it’s 5am local time; or when you restart your device. In order to fully disable Bluetooth or Wi-Fi, you’ll have to use the dedicated toggles in the Settings app.