diff --git a/JsonTest/System.Text.Json/AssemblyInfo.cs b/JsonTest/System.Text.Json/AssemblyInfo.cs
index 027623f..7f0aad4 100644
--- a/JsonTest/System.Text.Json/AssemblyInfo.cs
+++ b/JsonTest/System.Text.Json/AssemblyInfo.cs
@@ -32,5 +32,5 @@
 // You can specify all the values or you can default the Build and Revision Numbers 
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("2.0.0.11")]
-[assembly: AssemblyFileVersion("2.0.0.11")]
+[assembly: AssemblyVersion("2.0.1.11")]
+[assembly: AssemblyFileVersion("2.0.1.11")]
diff --git a/JsonTest/System.Text.Json/JsonParser.cs b/JsonTest/System.Text.Json/JsonParser.cs
index 4cfa709..75f1e4f 100644
--- a/JsonTest/System.Text.Json/JsonParser.cs
+++ b/JsonTest/System.Text.Json/JsonParser.cs
@@ -873,7 +873,7 @@ private decimal ParseDecimal(int outer)
         private Guid ParseGuid(int outer)
         {
             var s = ParseString(0);
-            if (!String.IsNullOrWhiteSpace(s))
+            if (!StringExtensions.IsNullOrWhiteSpace(s))
                 return new Guid(s);
             throw Error("Bad GUID");
         }
diff --git a/JsonTest/System.Text.Json/StringExtensions.cs b/JsonTest/System.Text.Json/StringExtensions.cs
new file mode 100644
index 0000000..62df863
--- /dev/null
+++ b/JsonTest/System.Text.Json/StringExtensions.cs
@@ -0,0 +1,8 @@
+namespace System {
+    public static class StringExtensions {
+        public static bool IsNullOrWhiteSpace(this string value) {
+            if (value == null) return true;
+            return string.IsNullOrEmpty(value.Trim());
+        }
+    }
+}
diff --git a/JsonTest/System.Text.Json/System.Text.Json.csproj b/JsonTest/System.Text.Json/System.Text.Json.csproj
index f825e64..0383ce8 100644
--- a/JsonTest/System.Text.Json/System.Text.Json.csproj
+++ b/JsonTest/System.Text.Json/System.Text.Json.csproj
@@ -10,8 +10,9 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>System.Text.Json</RootNamespace>
     <AssemblyName>System.Text.Json</AssemblyName>
-    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v3.5</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
+    <TargetFrameworkProfile />
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
@@ -44,6 +45,8 @@
     <Compile Include="JsonParser.cs" />
     <Compile Include="LambdaCompilation.cs" />
     <Compile Include="AssemblyInfo.cs" />
+    <Compile Include="StringExtensions.cs" />
+    <Compile Include="Tuple.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
diff --git a/JsonTest/System.Text.Json/Tuple.cs b/JsonTest/System.Text.Json/Tuple.cs
new file mode 100644
index 0000000..4f8a990
--- /dev/null
+++ b/JsonTest/System.Text.Json/Tuple.cs
@@ -0,0 +1,155 @@
+namespace System {
+    public class Tuple {
+        public static Tuple<T1> Create<T1>(T1 t1) {
+            return new Tuple<T1>(t1);
+        }
+
+        public static Tuple<T1, T2> Create<T1, T2>(T1 t1, T2 t2) {
+            return new Tuple<T1, T2>(t1, t2);
+        }
+
+        public static Tuple<T1, T2, T3> Create<T1, T2, T3>(T1 t1, T2 t2, T3 t3) {
+            return new Tuple<T1, T2, T3>(t1, t2, t3);
+        }
+
+        static Tuple<T1, T2, T3, T4> Create<T1, T2, T3, T4>(T1 t1, T2 t2, T3 t3, T4 t4) {
+            return new Tuple<T1, T2, T3, T4>(t1, t2, t3, t4);
+        }
+
+        static Tuple<T1, T2, T3, T4, T5> Create<T1, T2, T3, T4, T5>(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5) {
+            return new Tuple<T1, T2, T3, T4, T5>(t1, t2, t3, t4, t5);
+        }
+
+        static Tuple<T1, T2, T3, T4, T5, T6> Create<T1, T2, T3, T4, T5, T6>(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6) {
+            return new Tuple<T1, T2, T3, T4, T5, T6>(t1, t2, t3, t4, t5, t6);
+        }
+
+        static Tuple<T1, T2, T3, T4, T5, T6, T7> Create<T1, T2, T3, T4, T5, T6, T7>(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6, T7 t7) {
+            return new Tuple<T1, T2, T3, T4, T5, T6, T7>(t1, t2, t3, t4, t5, t6, t7);
+        }
+
+        static Tuple<T1, T2, T3, T4, T5, T6, T7, TRest> Create<T1, T2, T3, T4, T5, T6, T7, TRest>(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6, T7 t7, TRest Rest) {
+            return new Tuple<T1, T2, T3, T4, T5, T6, T7, TRest>(t1, t2, t3, t4, t5, t6, t7, Rest);
+        }
+    }
+
+    public class Tuple<T1> : Tuple {
+        public T1 Item1 { get; set; }
+
+        public Tuple(T1 Item1) {
+            this.Item1 = Item1;
+        }
+    }
+
+    public class Tuple<T1, T2> {
+        public T1 Item1 { get; set; }
+        public T2 Item2 { get; set; }
+
+        public Tuple(T1 Item1, T2 Item2) {
+            this.Item1 = Item1;
+            this.Item2 = Item2;
+        }
+    }
+
+    public class Tuple<T1, T2, T3> {
+        public T1 Item1 { get; set; }
+        public T2 Item2 { get; set; }
+        public T3 Item3 { get; set; }
+
+        public Tuple(T1 Item1, T2 Item2, T3 Item3) {
+            this.Item1 = Item1;
+            this.Item2 = Item2;
+            this.Item3 = Item3;
+        }
+    }
+
+    public class Tuple<T1, T2, T3, T4> {
+        public T1 Item1 { get; set; }
+        public T2 Item2 { get; set; }
+        public T3 Item3 { get; set; }
+        public T4 Item4 { get; set; }
+
+        public Tuple(T1 Item1, T2 Item2, T3 Item3, T4 Item4) {
+            this.Item1 = Item1;
+            this.Item2 = Item2;
+            this.Item3 = Item3;
+            this.Item4 = Item4;
+        }
+    }
+
+    public class Tuple<T1, T2, T3, T4, T5> {
+        public T1 Item1 { get; set; }
+        public T2 Item2 { get; set; }
+        public T3 Item3 { get; set; }
+        public T4 Item4 { get; set; }
+        public T5 Item5 { get; set; }
+
+        public Tuple(T1 Item1, T2 Item2, T3 Item3, T4 Item4, T5 Item5) {
+            this.Item1 = Item1;
+            this.Item2 = Item2;
+            this.Item3 = Item3;
+            this.Item4 = Item4;
+            this.Item5 = Item5;
+        }
+    }
+
+    public class Tuple<T1, T2, T3, T4, T5, T6> {
+        public T1 Item1 { get; set; }
+        public T2 Item2 { get; set; }
+        public T3 Item3 { get; set; }
+        public T4 Item4 { get; set; }
+        public T5 Item5 { get; set; }
+        public T6 Item6 { get; set; }
+
+        public Tuple(T1 Item1, T2 Item2, T3 Item3, T4 Item4, T5 Item5, T6 Item6) {
+            this.Item1 = Item1;
+            this.Item2 = Item2;
+            this.Item3 = Item3;
+            this.Item4 = Item4;
+            this.Item5 = Item5;
+            this.Item6 = Item6;
+        }
+    }
+
+    public class Tuple<T1, T2, T3, T4, T5, T6, T7> {
+        public T1 Item1 { get; set; }
+        public T2 Item2 { get; set; }
+        public T3 Item3 { get; set; }
+        public T4 Item4 { get; set; }
+        public T5 Item5 { get; set; }
+        public T6 Item6 { get; set; }
+        public T7 Item7 { get; set; }
+
+        public Tuple(T1 Item1, T2 Item2, T3 Item3, T4 Item4, T5 Item5, T6 Item6, T7 Item7) {
+            this.Item1 = Item1;
+            this.Item2 = Item2;
+            this.Item3 = Item3;
+            this.Item4 = Item4;
+            this.Item5 = Item5;
+            this.Item6 = Item6;
+            this.Item7 = Item7;
+        }
+    }
+
+    public class Tuple<T1, T2, T3, T4, T5, T6, T7, TRest> {
+        public T1 Item1 { get; set; }
+        public T2 Item2 { get; set; }
+        public T3 Item3 { get; set; }
+        public T4 Item4 { get; set; }
+        public T5 Item5 { get; set; }
+        public T6 Item6 { get; set; }
+        public T7 Item7 { get; set; }
+        public TRest Rest { get; set; }
+
+        public Tuple(T1 Item1, T2 Item2, T3 Item3, T4 Item4, T5 Item5, T6 Item6, T7 Item7, TRest Rest) {
+            this.Item1 = Item1;
+            this.Item2 = Item2;
+            this.Item3 = Item3;
+            this.Item4 = Item4;
+            this.Item5 = Item5;
+            this.Item6 = Item6;
+            this.Item7 = Item7;
+            this.Rest = Rest;
+        }
+    }
+}