The next version of ASP.NET is more than just a simple upgrade from the current version. Instead the next version will be quite different and re-engineered from the ground up. Why is this a big change? Microsoft wants ASP.NET Core to be the stack to build lean and modern web applications. These applications can run both on your own servers as well as in the cloud. To meet these ambitious goals they have decided to remove old and deprecated API’s. This means they have started all over with a completely new unified stack. This new stack is not just a replacement for the ageing System.Web.dll assembly. Instead they are all in and are even including a completely new CLR named CoreCLR. This CoreCLR is optimized for cloud hosted applications. As a final twist this new CoreCLR is no longer tied to just Windows. In the future they will also be support in Linux and Mac OS and can even run your application in a Docker container.