how to target .NET 4 http://msdn.microsoft.com/en-us/library/bb398202.aspx Target your project Target your project change the Target framework version http://msdn.microsoft.com/en-us/library/bb398202.aspx https://msdn.microsoft.com/en-us/library/bb398202.aspx http://msdn.microsoft.com/en-us/library/bb398202.aspx How to: Target a Version of the .NET Framework https://msdn.microsoft.com/en-us/library/bb398202.aspx How to: Target a Version of the .NET Framework