.NET Core 3.1将于 2022 年 12 月 13 日结束支持.此后,Microsoft 将不再为 .NET Core 3.1 Provide service updates or technical support.We recommend migrating to as soon as possible .NET 6.If you are still using it after the end of the support date .NET Core 3.1,Then you need to update your app to .NET 6 或 .NET 7 to continue to receive relevant support and continue to receive .NET 更新.

.NET Core 3.1 The application will continue to work after the end of support.They won't change anything.But after support ends.NET 6 each security patch in 都是.NET Core 3.1 Potential documented and unpatched security vulnerabilities of the application.

您可以了解有关 .NET More information on publishing policies：

Update your application

如果您的应用程序使用 NET Core 3.1,We strongly recommend that you migrate your application to .NET 6 —— a supported one LTS 版本.您可以从 .NET 网站 下载 .NET 6 .

If you are an end user,We recommend that you contact the vendor that manages your software,Confirm if an updated version of the software is required and available.The rest of this article is for software vendors and developers.

升级到 .NET 6

• 打开项目文件（.csproj、.vbproj 或 *.fsproj 文件）.
• 将<TargetFramework>netcoreapp3.1</TargetFramework> 更改为 <TargetFramework>net6.0</TargetFramework>.

您也可以查看.NET 6 兼容性指南.

更新开发环境

Except for the software you deliver to your customers,The computer you are using for development probably has it installed .NET Core 3.1——Either independently or by Visual Studio 安装的.

You can check from the command line .NET Core 3.1 stand-alone installation.在 Windows 计算机上,打开命令提示符并转到 %ProgramFiles%dotnet 文件夹.在 macOS 或 Linux 上,打开终端窗口.

然后输入以下命令：dotnet –list-runtimes

如果您使用 Visual Studio 2019 16.11 或 17.0 或 Visual Studio 2022 17.2,based on the installed workload,You may also have installed .NET Core 3.1 作为 Visual Studio 的必需组件,You need to know about some upcoming related changes.

从 Visual Studio 2019 16.11、Visual Studio 2019 17.0 和 Visual Studio 2022 17.2 的 2022 年 12 Monthly service update begins,Visual Studio 中的 .NET Core 3.1 Components will be changed to unsupported and optional.This means it can be installed without .NET Core 3.1 的情况下安装 Visual Studio 中的工作负载.请注意,Existing installations will not be affected,And any previously installed workloads and components will remain installed,直到在 Visual Studio Deselect components or workloads in the installer.虽然您可以在 Visual Studio Reselect this optional component in and reinstall it,但我们强烈建议您使用 .NET 6 和 Visual Studio 2022 to build on the supported ones .NET 运行时上运行的应用程序.

注意：If you are migrating your application to .NET 6,Some breaking changes may affect you.We recommend that you do this first兼容性检查. 

Here are some related resources for you to check out：

• .NET 下载
• .NET 兼容性
• .NET 部署
• .NET 支持政策

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