AspNetCore.Docs/aspnetcore/fundamentals/metapackage-app.md

title	author	description	manager	monikerRange	ms.author	ms.date	ms.prod	ms.technology	ms.topic	uid
Microsoft.AspNetCore.App metapackage for ASP.NET Core 2.1 and later	Rick-Anderson	The Microsoft.AspNetCore.App metapackage includes all supported ASP.NET Core and Entity Framework Core packages.	wpickett	>= aspnetcore-2.1	riande	09/20/2017	asp.net-core	aspnet	article	fundamentals/metapackage-app

Microsoft.AspNetCore.App metapackage for ASP.NET Core 2.1

This feature requires ASP.NET Core 2.1 and later targeting .NET Core 2.1 and later.

The Microsoft.AspNetCore.App metapackage for ASP.NET Core:

• Does not include third-party dependencies except for Json.NET, Remotion.Linq, and IX-Async. These 3rd-party dependencies are deemed necessary to ensure the major frameworks features function.
• Includes all supported packages by the ASP.NET Core team except those that contain third-party dependencies (other than those previously mentioned).
• Includes all supported packages by the Entity Framework Core team except those that contain third-party dependencies (other than those previously mentioned).

All the features of ASP.NET Core 2.1 and later and Entity Framework Core 2.1 and later are included in the Microsoft.AspNetCore.App package. The default project templates targeting ASP.NET Core 2.1 and later use this package. We recommend applications targeting ASP.NET Core 2.1 and later and Entity Framework Core 2.1 and later use the Microsoft.AspNetCore.App package.

The version number of the Microsoft.AspNetCore.App metapackage represents the ASP.NET Core version and Entity Framework Core version.

Using the Microsoft.AspNetCore.App metapackage provides version restrictions that protect your app:

• If a package is included that has a transitive (not direct) dependency on a package in Microsoft.AspNetCore.App, and those version numbers differ, NuGet will generate an error.
• Other packages added to your app cannot change the version of packages included in Microsoft.AspNetCore.App.
• Version consistency ensures a reliable experience. Microsoft.AspNetCore.App was designed to prevent untested version combinations of related bits being used together in the same app.

Applications that use the Microsoft.AspNetCore.App metapackage automatically take advantage of the ASP.NET Core shared framework. When you use the Microsoft.AspNetCore.App metapackage, no assets from the referenced ASP.NET Core NuGet packages are deployed with the application — the ASP.NET Core shared framework contains these assets. The assets in the shared framework are precompiled to improve application startup time. For more information, see "shared framework" in .NET Core distribution packaging.

The following .csproj project file references the Microsoft.AspNetCore.App metapackage for ASP.NET Core:

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.App" />
  </ItemGroup>

</Project>

The preceding markup represents a typical ASP.NET Core 2.1 and later template. It doesn't specify a version number for the Microsoft.AspNetCore.App package reference. When the version is not specified, an implicit version is specified by the SDK, that is, Microsoft.NET.Sdk.Web. We recommend relying on the implicit version specified by the SDK and not explicitly setting the version number on the package reference. You can leave a GitHub comment at Discussion for the Microsoft.AspNetCore.App implicit version.

The implicit version is set to major.minor.0 for portable apps. The shared framework roll-forward mechanism will run the app on the latest compatible version among the installed shared frameworks. To guarantee the same version is used in development, test, and production, ensure the same version of the shared framework is installed in all environments. For self contained apps, the implicit version number is set to the major.minor.patch of the shared framework bundled in the installed SDK.

Specifying a version number on the Microsoft.AspNetCore.App reference does not guarantee that version of the shared framework will be chosen. For example, suppose version "2.1.1" is specified, but "2.1.3" is installed. In that case, the app will use "2.1.3". Although not recommended, you can disable roll forward (patch and/or minor). For more information regarding dotnet host roll-forward and how to configure its behavior, see dotnet host roll forward.

The Microsoft.AspNetCore.App metapackage is not a traditional package that is updated from NuGet. Similar to Microsoft.NETCore.App, Microsoft.AspNetCore.App represents a shared runtime, which has special versioning semantics handled outside of NuGet. For more information, see Packages, metapackages and frameworks.

If your application previously used Microsoft.AspNetCore.All, see Migrating from Microsoft.AspNetCore.All to Microsoft.AspNetCore.App.