Last November Microsoft announced ASP.NET 5 as a new open source and cross-platform framework for building modern Web and cloud applications using the Microsoft .NET Framework. We (the ASP.NET development team, of which I’m a part) released ASP.NET 5 Preview along with Visual Studio 2015 Preview at the Connect(); event in New York City. I introduced you to the ASP.NET 5 runtime and its new Visual Studio project system in the “Introducing the ASP.NET 5 Preview” article from the special Dec. 15, 2014, Issue of MSDN Magazine (bit.ly/1K4PY4U). Since that last look at ASP.NET 5 in December there have been two more preview releases of ASP.NET 5: Beta2 with Visual Studio 2015 CTP 5, and Beta3 with Visual Studio 2015 CTP 6. With each release, the framework continues to evolve and improve. In many cases, these improvements were generously contributed by the .NET community through the public ASP.NET project on GitHub (bit.ly/1DaY7Cd). In this article, I’ll take a deeper look under the hood of the new ASP.NET 5 runtime to see what’s changed in the most recent release.