Based on XMLRPC dot NET by Charles Cook Source: http://xml-rpc.net/ and https://code.google.com/p/xmlrpcnet/

To install in your project:

PM> Install-Package xmlrpc-universal

XMLRPC-Universal is a library for consuming XML RPC services from a Windows UWP application. For each web service, you should create a Proxy class that looks like this:

using Windows.Data.Xml.Rpc;

[XmlRpcUrl("http://www.cookcomputing.com/xmlrpcsamples/RPC2.ashx")]
class TestProxy : XmlRpcClientProtocol
{
    //Declare async RPC methods here
}

To implement the RPC methods, the declarations should look like this:

[XmlRpcMethod("examples.getStateName")]
public async Task<String> GetStateName(int stateIndex)
{
    //You must pass your parameters as an object array.
    return await InvokeAsync<String>(new object[] { number });
    
}

There is a sample application included.