---
title: Migrate from ASP.NET Core 2.0 to 2.1
author: rick-anderson
description: This article covers the basics of migrating an ASP.NET Core 2.0 app to 2.1.
ms.author: riande
ms.date: 05/30/2018
uid: migration/20_21
---
# Migrate from ASP.NET Core 2.0 to 2.1
By [Rick Anderson](https://twitter.com/RickAndMSFT)
See [What's new in ASP.NET Core 2.1](xref:aspnetcore-2.1) for an overview of the new features in ASP.NET Core 2.1.
This article:
* Covers the basics of migrating an ASP.NET Core 2.0 app to 2.1.
* Provides an overview of the changes to the ASP.NET Core web application templates.
A quick way to get an overview of the changes in 2.1 is to:
* Create an ASP.NET Core 2.0 web app named WebApp1.
* Commit the WebApp1 in a source control system.
* Delete WebApp1 and create an ASP.NET Core 2.1 web app named WebApp1 in the same place.
* Review the changes in the 2.1 version.
This article provides an overview on migration to ASP.NET Core 2.1. It does not contain a complete list of all changes needed to migrate to version 2.1. Some projects might require more steps depending on the options selected when the project was created and modifications made to the project.
## Update the project file to use 2.1 versions
Update the *.csproj* project file:
* Change `netcoreapp2.0` to the 2.1 version, that is `netcoreapp2.1`.
* Replace the version specified "Microsoft.AspNetCore.All" package reference with the versionless "Microsoft.AspNetCore.App" package reference. You may need to add dependencies that were removed from "Microsoft.AspNetCore.All". See [Migrating from Microsoft.AspNetCore.All to Microsoft.AspNetCore.App](xref:fundamentals/metapackage#migrate) and [Microsoft.AspNetCore.App metapackage](xref:fundamentals/metapackage-app). If you're targetting the .NET Framework:
* Add individual package references instead of a meta package reference.
* Update each package reference to 2.1.
* Remove all references to `` elements for "Microsoft.AspNetCore", "Microsoft.VisualStudio", and "Microsoft.EntityFrameworkCore" packages. These tools have been replaced by global tools.
The following markup shows the template generated 2.0 *.csproj* project file:
[!code-xml[Main](20_21/sample/WebApp20.csproj)]
The following markup shows the template generated 2.1 *.csproj* project file:
[!code-xml[Main](20_21/sample/WebApp21.csproj)]
## Rules for projects targeting the shared runtime
ASP.NET Core includes the following shared runtimes:
* [Microsoft.AspNetCore.App](xref:fundamentals/metapackage-app)
* [Microsoft.AspNetCore.All](xref:fundamentals/metapackage)
Rules for projects targeting the shared runtime:
* Projects referencing the `Microsoft.AspNetCore.All` or `Microsoft.AspNetCore.App` packages must set the project's SDK to `Microsoft.NET.Sdk.Web` at the top of the project file (``).
* Projects referencing packages or projects that transitively reference `Microsoft.AspNetCore.All` or `Microsoft.AspNetCore.App`:
* Must set the project's SDK to `Microsoft.NET.Sdk.Web` at the top of the project file (``).
* Must reference the same shared runtime package. If LibraryA references `Microsoft.AspNetCore.App`, any projects referencing LibraryA must also reference `Microsoft.AspNetCore.App`.
* Executable projects (projects that contain apps that are launched with `dotnet run` or apps that run and test projects for apps) must not specify a version for `Microsoft.AspNetCore.App`. The SDK specifies the version implicitly via ``.
* Referenced projects (projects that aren't the entry point and the project references `Microsoft.AspNetCore.All` or `Microsoft.AspNetCore.App`) must specify a package version.
## Changes to take advantage of the new code-based idioms that are recommended in ASP.NET Core 2.1
### Changes to Main
The following images show the changes made to the templated generated *Program.cs* file.
The preceding image shows the 2.0 version with the deletions in red.
The following image shows the 2.1 code. The code in green replaced the 2.0 version:
The following code shows the 2.1 version of *Program.cs*:
[!code-csharp[Main](20_21/sample/Program.cs?name=snippet)]
The new `Main` replaces the call to `BuildWebHost` with [CreateWebHostBuilder](/dotnet/api/microsoft.aspnetcore.mvc.testing.webapplicationfactory-1.createwebhostbuilder). [IWebHostBuilder](/dotnet/api/microsoft.aspnetcore.hosting.iwebhostbuilder) was added to support a new [integration test infrastructure](xref:test/integration-tests).
### Changes to Startup
The following code shows the changes to 2.1 template generated code. All changes are newly added code, except that `UseBrowserLink` has been removed:
[!code-csharp[Main](20_21/sample/Startup.cs?highlight=3,4,21-26,30,42,45,47)]
The preceding code changes are detailed in:
* [GDPR support in ASP.NET Core](xref:security/gdpr) for `CookiePolicyOptions` and `UseCookiePolicy`.
* [HTTP Strict Transport Security Protocol (HSTS)](xref:security/enforcing-ssl#http-strict-transport-security-protocol-hsts) for `UseHsts`.
* [Require HTTPS](xref:security/enforcing-ssl#require-https) for `UseHttpsRedirection`.
* [SetCompatibilityVersion](xref:fundamentals/startup#setcompatibilityversion) for `SetCompatibilityVersion(CompatibilityVersion.Version_2_1)`.
## Changes to authentication code
ASP.NET Core 2.1 provides [ASP.NET Core Identity](xref:security/authentication/identity) as a [Razor Class Library](xref:razor-pages/ui-class) (RCL).
The default 2.1 Identity UI doesn't currently provide significant new features over the 2.0 version. Replacing Identity with the RCL package is optional. The advantages to replacing the template generated Identity code with the RCL version include:
* Many files are moved out of your source tree.
* Any bug fixes or new features to Identity are included in the [Microsoft.AspNetCore.App metapackage](xref:fundamentals/metapackage-app). You automatically get the updated Identity when `Microsoft.AspNetCore.App` is updated.
If you've made non-trivial changes to the template generated Identity code:
* The preceding advantages may not justify converting to the the RCL version.
* You can keep your ASP.NET Core 2.0 Identity code, it's fully supported.
Identity 2.1 exposes endpoints with the `Identity` area. For example, the follow table shows examples of Identity endpoints that change from 2.0 to 2.1:
| 2.0 URL | 2.1 URL |
| --------------- | ------------ |
| /Account/Login | /Identity/Account/Login |
| /Account/Logout | /Identity/Account/Logout |
| /Account/Manage | /Identity/Account/Manage |
Applications that have code using Identity and replace 2.0 Identity UI with the 2.1 Identity Library need to take into account Identity URLs have `/Identity` segement prepended to the URIs. One way to handle the new Identity endpoints is to set up redirects, for example from `/Account/Login` to `/Identity/Account/Login`.
### Update Identity to version 2.1
The following options are available to update Identity to 2.1.
* Use the Identity UI 2.0 code with no changes. Using Identity UI 2.0 code is fully supported. This is a good approach when signficant changes have been made to the generated Identity code.
* Delete your existing Identity 2.0 code and [Scaffold Identity](xref:security/authentication/scaffold-identity) into your project. Your project will use the [ASP.NET Core Identity](xref:security/authentication/identity) [Razor Class Library](xref:razor-pages/ui-class). You can generate code and UI for any of the Identity UI code that you modified. Apply your code changes to the newly scaffolded UI code.
* Delete your existing Identity 2.0 code and [Scaffold Identity](xref:security/authentication/scaffold-identity) into your project with the option to **Override all files**.
### Replace Identity 2.0 UI with the Identity 2.1 Razor Class Library
This section outlines the steps to replace the ASP.NET Core 2.0 template generated Identity code with the [ASP.NET Core Identity](xref:security/authentication/identity) [Razor Class Library](xref:razor-pages/ui-class). The following steps are for a Razor Pages project, but the approach for an MVC project is similar.
* Verify the [project file is updated to use 2.1 versions](#update-the-project-file-to-use-21-versions)
* Delete the following folders and all the files in them:
* *Controllers*
* *Pages/Account/*
* *Extensions*
* Build the project.
* [Scaffold Identity](xref:security/authentication/scaffold-identity) into your project:
* Select the projects exiting *_Layout.cshtml* file.
* Select the **+** icon on the right side of the **Data context class**. Accept the default name.
* Select **Add** to create a new Data context class. Creating a new data context is required for to scaffold. You remove the new data context in the next section.
### Update after scaffolding Identity
* Delete the Identity scaffolder generated `IdentityDbContext` derrived class in the *Areas/Identity/Data/* folder.
* Delete *Areas/Identity/IdentityHostingStartup.cs*
* Update the *_LoginPartial.cshtml* file:
* Move *Pages/_LoginPartial.cshtml* to *Pages/Shared/_LoginPartial.cshtml*
* Add `asp-area="Identity"` to the form and achor links.
* Update the `` element to `