- Middleware is quite similar between Katana and Core but you use HttpContext instead of IOwinContext.
- Startup.cs is similar but there’s much more DI support.
- WebApi has been merged into MVC
- DelegatingHandler is gone, use middleware instead.
- HttpConfiguration has been split up into Routing and MvcOptions.
Also https://devblogs.microsoft.com/aspnet/katana-asp-net-5-and-bridging-the-gap/