This doesn’t mean that all public WiFi is bad, it’s just that this is something to take note of. With iOS 10, Apple is hoping to keep its users more informed when connecting to unsecured WiFi networks. This will be accomplished through a warning message in which users will be informed when they are connected to an open network.
As you can see in screenshot above, it shows the warning message that will be displayed to users under the WiFi section of the Settings app. This will only be a warning and you will still be allowed to connect to the network. The message also advises uses to configure their routers to turn AES encryption if possible.
This could come in handy if you’ve just setup a new network at home and forgot to enable encryption, or if you’re at someone’s house who doesn’t have the encryption either.