What Does .NET 5 Mean To You 

Announcing Entity Framework 6.3 Preview with .NET Core Support 

"If you rely on legacy features in WCF, ASPX pages, or other older technologies then they likely don't have any path forward after framework 4.8."  

.NET 4.8 is the end of the road for .NET Framework.
.NET 5 = .NET Core vNext

All future investment in .NET will be in .NET Core. This includes:  Runtime,   JIT , AOT,   GC,  BCL (Base Class Library),  C#, VB .NET , F#, ASP.NET,  Entity Framework ,  ML.NET,  WinForms, WPF  and Xamarin.  

New JSON Serialization
In 3.0-preview5, ASP.NET Core MVC adds supports for reading and writing JSON using System.Text.Json. The System.Text.Json serializer can read and write JSON asynchronously, and is optimized for UTF-8 text making it ideal for REST APIs and backend applications. 

It includes a new Json serializer, support for publishing single file executables, an update to runtime roll-forward, and changes in the BCL. 

The team said that “most of their effort to improve the .NET Core Docker experience in the last year has been focused on .NET Core 3.0.” “This is the first release in which we’ve made substantive runtime changes to make CoreCLR much more efficient, honor Docker resource limits better by default, and offer more configuration for you to tweak”.  

 CoreRT is an experimental cross-platform open source .NET runtime specialized for AOT compilation.