diff --git a/Lidgren XNA Extensions/Lidgren XNA Extensions/Lidgren XNA Extensions.csproj b/Lidgren XNA Extensions/Lidgren XNA Extensions/Lidgren XNA Extensions.csproj
index aa2bc4e..9f672e7 100644
--- a/Lidgren XNA Extensions/Lidgren XNA Extensions/Lidgren XNA Extensions.csproj	
+++ b/Lidgren XNA Extensions/Lidgren XNA Extensions/Lidgren XNA Extensions.csproj	
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="3.5" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -10,7 +10,7 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>Lidgren.Network.Xna</RootNamespace>
     <AssemblyName>Lidgren.Network.Xna</AssemblyName>
-    <TargetFrameworkVersion>v3.5</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
@@ -31,7 +31,7 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="Microsoft.Xna.Framework, Version=3.1.0.0, Culture=neutral, PublicKeyToken=6d5c3888ef60e27d, processorArchitecture=x86" />
+    <Reference Include="Microsoft.Xna.Framework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=842cf8be1de50553, processorArchitecture=x86" />
     <Reference Include="System" />
     <Reference Include="System.Core">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>