2.1

SignalR: SignalR has been rewritten for ASP.NET Core 2.1. ASP.NET Core SignalR includes a number of improvements:

1. A simplified scale-out model.
2. A new JavaScript client with no jQuery dependency.
3. A new compact binary protocol based on MessagePack.
4. Support for custom protocols.
5. A new streaming response model.
6. Support for clients based on bare WebSockets.

Razor class libraries

Identity UI library & scaffolding

Integration tests: A new package is introduced that streamlines test creation and execution

[ApiController]: attribute has also been added as the way to opt in to Web API-specific conventions and behaviors.

ActionResult<T>: is a new type added to allow an app to return either a response type or any other action result (similar to IActionResult), while still indicating the response type.

IHttpClientFactory: ASP.NET Core 2.1 includes a new IHttpClientFactory service that makes it easier to configure and consume instances of HttpClient in apps.