.NET Platform Overview and Roadmap

Migrating from .NET Framework to .NET Core 3.0

Several technologies and APIs present in the .NET Framework are not available in .NET Core. If your application or library requires these APIs, consider finding alternatives or continue using the .NET Framework. .NET Core does not support the following technologies and APIs:

• Windows Communication Foundation (WCF) servers (WCF clients are supported)
• .NET remoting

Additionally, a number of .NET APIs can only be used in Microsoft Windows environments. The following list shows a few examples of these Windows-specific APIs:

• Microsoft.Win32.Registry
• System.AppDomains
• System.Security.Principal.Windows

Consider using the .NET Portability Analyzer to identify API gaps and potential replacements. For example, enter the following command to find out how much of the API used by your .NET Framework 4.6 application is supported by .NET Core 2.1.

$ dotnet /path/to/ApiPort.dll analyze -f . -r html --target '.NET Framework,Version=4.6' --target '.NET Core,Version=2.1'

Refer to the following Microsoft articles when migrating from .NET Framework.

• For general guidelines, see Porting to .NET Core from .NET Framework.
• For porting libraries, see Porting to .NET Core - Libraries.
• For migrating to ASP.NET Core, see Migrating to ASP.NET Core.

NOTE

Several APIs that are not supported in the out-of-the-box version of .NET Core may be available from the Microsoft.Windows.Compatibility nuget package. 

Documentation: http://docs.dot.net

.NET Core: https://www.microsoft.com/net/core

Introducing .NET Core: https://blogs.msdn.microsoft.com/dotnet/2014/12/04/introducing-net-core/

.NET Standard Library: https://github.com/dotnet/standard

.NET Core framework source code: https://github.com/dotnet/corefx/tree/master/src

ASP.NET Core benchmarks: https://github.com/aspnet/benchmarks

.NET Core Docker image: https://hub.docker.com/r/microsoft/dotnet/

.NET Standard

The .NET Standard is a formal specification of .NET APIs that are intended to be available on all .NET implementations. You can think of it as an “interface” for various .NET implementations (such as .NET Core, .NET Framework, and Mono), while the .NET implemenatons (such as .NET Core, .NET Framework, and Mono) all “implement” a version of .NET Standard.

.NET Standard allows libraries to build against the agreed on set of common APIs, ensuring they can be used in any .NET application—mobile, desktop, IoT, web, or anywhere you write .NET code.

.NET Standard is versioned. Each new version adds more APIs. When a library is built against a certain version of .NET Standard, it can run on any .NET implementation that implements that version of .NET Standard (or higher).

The following table lists the minimum platform versions that support each .NET Standard version. That means that later versions of a listed platform also support the corresponding .NET Standard version. For example, .NET Core 2.2 supports .NET Standard 2.0 and earlier.