iPhone 4 doesn't prompt password verification when attempting to connect to AirPlay I'm trying to connect to an Airplay device in my class from an iPhone 4 (MD197LL/A) running iOS 7.1.2 (11D257), and when I select the device I would like to mirror to, it only displays the animation of the button being clicked, and displays the blue checkmark as if I had sucessfully connected. 

However, the screen doesn't mirror the device, nor does it prompt for me to enter the passcode or display the it on the screen. Not only this, but it also doesn't show the one bar drop-down mirror switch when I select the device.

I am on the same network as my iPad 3 (MD329LL/A) running iOS 8.4 (12H143), which does prompt me to enter a passkey and displays it on the sceeen.

Note: It does this for every single device on the network, not exclusively the one I'm trying to connect to.
I spent a while recently pondering what I think is the same issue.

Eventually I found that AirPlay Mirroring requires an iPhone 4S or later.

So audio should play wirelessly from the iPhone 4, but screen mirroring won't work.

Hope that helps.