In visual Studio 2015, in my solution, I have a Logic tier (class library) project that is added to the references of a WinForm project. No, I am going to add a new Windows Universal project and added the same logic tier (class library) into it. However, visual studio doesn't allow me to add the class library as a reference to the universal app, I get an error message.
The question is, What kind of class library that can be added to the references of Universal project as well as to the Winform projects withen the same solution?
Update: the message is "Enable to add a reference to project 'project-name' ."