The Microsoft .NET Framework 4.5 Beta is a highly compatible, in-place update to the .NET Framework 4. By using the .NET Framework 4.5 Beta together with the C# or Visual Basic programming languages, you can write Windows Metro style apps. The .NET Framework 4.5 Beta includes significant language and framework enhancements for C# and Visual Basic so that you can harness asynchrony, the blending of control flow in synchronous code, a responsive UI, and web app scalability. The .NET Framework 4.5 Beta adds substantial improvements to other functional areas such as ASP.NET, Managed Extensibility Framework (MEF), Windows Communication Foundation (WCF), Windows Workflow Foundation (WF), and Windows Identity Foundation (WIF). The .NET Framework 4.5 Beta delivers better performance, reliability, and security.