I've been frustrated to find that as a result of Microsoft.Phone (and more importantly Microsoft.Phone.Tasks) not being supported in Windows Phone 8.1 XAML launching a specific phone setting from your application has changed. It is however supported in Windows Phone Silverlight 8 and 8.1.
Previously the code for opening a settings page (in this example the Bluetooth Settings Page) would have followed:
ConnectionSettingsTask connectionSettingsTask = new ConnectionSettingsTask(); connectionSettingsTask.ConnectionSettingsType = ConnectionSettingsType.Bluetooth; connectionSettingsTask.Show();
The new syntax for opening a settings page (again in this example Bluetooth) in Windows 8.1 Phone XAML is as follows:
*Notice the addition of the :/// (makes all the difference in the world)
Hopefully that saves you some time searching because it took me a while before i found anything remotely useful for Windows Phone 8.1.