Microsoft released .NET Core 1.0 today along with ASP.NET Core 1.0 and Entity Framework Core 1.0.
I have been working with the .NET Framework for a long time, so seeing Microsoft release a version of .NET that runs on Windows, Mac and Linux still feels a little strange.
.NET Core is not a replacement for the full .NET Framework at this point, and Microsoft is pretty clear that there are still features missing. For existing applications I do not see any reason to start moving everything over.
For new applications though, this is definitely something worth paying attention to.
The biggest thing that interests me is the ability to build and run .NET applications outside of Windows. The platform is also open source, modular, and designed so different versions can run side-by-side.
ASP.NET Core has changed quite a bit as well. It no longer depends on System.Web, includes built-in dependency injection, and combines MVC and Web API into a single framework.
There is a lot here that I need to spend some time with.
I am not ready to move my existing applications away from the .NET Framework, but .NET Core 1.0 feels like the beginning of a very different direction for .NET.
Further reading: the .NET Core transition
This announcement captures my first impressions in 2016. To follow how the platform became more practical, see why .NET Core 2.0 started to feel ready and what .NET Core 3.0 meant for existing Windows applications.