diff --git a/modelderivative/source/LocalMarshalling.cs b/modelderivative/source/LocalMarshalling.cs
index 7a3324d..73b0986 100644
--- a/modelderivative/source/LocalMarshalling.cs
+++ b/modelderivative/source/LocalMarshalling.cs
@@ -48,6 +48,10 @@ public static string ParameterToString(object obj)
                 // https://docs.microsoft.com/en-us/dotnet/standard/base-types/standard-date-and-time-format-strings#Roundtrip
                 return ((DateTime)obj).ToString ("o");
             }
+            if (obj is Boolean)
+            {
+                return (Boolean)obj ? "true" : "false";
+            }
             else
             {
                 return Convert.ToString (obj);
diff --git a/samples/modelderivative.cs b/samples/modelderivative.cs
index 3125d68..4e3610a 100644
--- a/samples/modelderivative.cs
+++ b/samples/modelderivative.cs
@@ -297,7 +297,7 @@ public async Task GetDerivativeHeadersAsync()
 
         #endregion
 
-        public async void Main()
+        public async static Task Main()
         {
 
             // Initialise SDKManager & ModelDerivativeClient