I want to submit an app I wrote to the Windows store. All the examples I have found about implementing trial functionality in an app, seem to be dated. For example, most tell you to add the using directive 'using Microsoft.Phone.MarketPlace; which causes Visual Studio 2013 to ask if I have forgotten an assembly reference. Am I supposed to add a NuGet package or something? Any help would be greatly appreciated.
using Microsoft.Phone.Marketplace;
Can anyone suggest a good, reliable, and current source of information?