I'm trying to set the UIRequiredDeviceCapabilities properties in my Info.plist file. My app requires a persistent network connection. If I look at the definition for the "wifi" key, it says:
Include this key if your application requires access to the networking features of the device.
So: does the "wifi" key indicate that I need WiFi, as the key name would suggest? Or does it mean that I simply need network access, as the key definition would suggest?
Without this key, the iPhone will disable wifi after a certain amount of inactivity. With this key, the wifi is kept permanently enabled for your app.
If you need persistent wifi you should use the key UIRequiresPersistentWiFi.
The UIRequiredDeviceCapabilities key does just what the name indicates, specifies which capabilities your app needs the device to have. Be it wifi, gps, magnetometer, etc.
First of all, UIRequiresPersistentWiFi does not pertain just to WiFi, but is simply a way to state that your program is a network application and will be using any connection persistently. This in particular was mentioned by Apple developer doing WWDC presentation on network programming (last year, I think).
Second, the wifi key of required device capabilities does seem to pertain to the WiFi in particular. The Unicom iPhone available in China has WiFi turned off (but is capable of connecting to network using cellular connection), and I've heard of reports that wifi key is (or at least was) causing trouble with installations.