# Migrating from OpenIddict to IdentityServer4 Step by Step Guide
ABP startup templates use `OpenIddict` OpenID provider from v6.0.0 by default and `IdentityServer` projects are renamed to `AuthServer` in tiered/separated solutions. Since OpenIddict is the default OpenID provider library for ABP templates since v6.0, you may want to keep using [IdentityServer4](https://github.com/IdentityServer/IdentityServer4) library, even it is **archived and no longer maintained by the owners**. ABP doesn't provide support for newer versions of IdentityServer. This guide provides layer-by-layer guidance for migrating your existing [OpenIddict](https://github.com/openiddict/openiddict-core) application to IdentityServer4.
## IdentityServer4 Migration Steps
Use the `abp update` command to update your existing application. See [Upgrading docs](../Upgrading.md) for more info. Apply required migrations by following the [Migration Guides](Index.md) based on your application version.
### Domain.Shared Layer
- In **MyApplication.Domain.Shared.csproj** replace **project reference**:
```csharp
```
with
```csharp
```
- In **MyApplicationDomainSharedModule.cs** replace usings and **module dependencies:**
```csharp
using Volo.Abp.OpenIddict;
...
typeof(AbpOpenIddictDomainSharedModule)
```
with
```csharp
using Volo.Abp.IdentityServer;
...
typeof(AbpIdentityServerDomainSharedModule)
```
### Domain Layer
- In **MyApplication.Domain.csproj** replace **project references**:
```csharp
```
with
```csharp
```
- In **MyApplicationDomainModule.cs** replace usings and **module dependencies**:
```csharp
using Volo.Abp.OpenIddict;
using Volo.Abp.PermissionManagement.OpenIddict;
...
typeof(AbpOpenIddictDomainModule),
typeof(AbpPermissionManagementDomainOpenIddictModule),
```
with
```csharp
using Volo.Abp.IdentityServer;
using Volo.Abp.PermissionManagement.IdentityServer;
...
typeof(AbpIdentityServerDomainModule),
typeof(AbpPermissionManagementDomainIdentityServerModule),
```
#### OpenIddictDataSeedContributor
DataSeeder is the most important part for starting the application since it seeds the initial data for both OpenID providers.
- Create a folder named *IdentityServer* under the Domain project and copy the [IdentityServerDataSeedContributor.cs](https://github.com/abpframework/abp-samples/blob/master/Ids2OpenId/src/Ids2OpenId.Domain/IdentityServer/IdentityServerDataSeedContributor.cs) under this folder. **Rename** all the `OpenId2Ids` with your project name.
- Delete *OpenIddict* folder that contains `OpenIddictDataSeedContributor.cs` which is no longer needed.
### EntityFrameworkCore Layer
If you are using MongoDB, skip this step and check the *MongoDB* layer section.
- In **MyApplication.EntityFrameworkCore.csproj** replace **project reference**:
```csharp
```
with
```csharp
```
- In **MyApplicationEntityFrameworkCoreModule.cs** replace usings and **module dependencies**:
```csharp
using Volo.Abp.OpenIddict.EntityFrameworkCore;
...
typeof(AbpOpenIddictEntityFrameworkCoreModule),
```
with
```csharp
using Volo.Abp.IdentityServer.EntityFrameworkCore;
...
typeof(AbpIdentityServerEntityFrameworkCoreModule),
```
- In **MyApplicationDbContext.cs** replace usings and **fluent api configurations**:
```csharp
using Volo.Abp.OpenIddict.EntityFrameworkCore;
...
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
/* Include modules to your migration db context */
...
builder.ConfigureOpenIddict();
```
with
```csharp
using Volo.Abp.IdentityServer.EntityFrameworkCore;
...
using Volo.Abp.OpenIddict.EntityFrameworkCore;
...
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
/* Include modules to your migration db context */
...
builder.ConfigureIdentityServer();
```
> Not: You need to create new migration after updating the fluent api. Navigate to *EntityFrameworkCore* folder and add a new migration. Ex, `dotnet ef migrations add Updated_To_IdentityServer `
### MongoDB Layer
If you are using EntityFrameworkCore, skip this step and check the *EntityFrameworkCore* layer section.
- In **MyApplication.MongoDB.csproj** replace **project reference**:
```csharp
```
with
```csharp
```
- In **MyApplicationMongoDbModule.cs** replace usings and **module dependencies**:
```csharp
using Volo.Abp.OpenIddict.MongoDB;
...
typeof(AbpOpenIddictMongoDbModule),
```
with
```csharp
using Volo.Abp.IdentityServer.MongoDB;
...
typeof(AbpIdentityServerMongoDbModule),
```
### DbMigrator Project
- In `appsettings.json` **replace OpenIddict section with IdentityServer** since IdentityServerDataSeeder will be using these information for initial data seeding:
```json
"IdentityServer": { // Rename OpenIddict to IdentityServer
"Clients ": { // Rename Applications to Clients
...
}
}
```
### Test Project
- In **MyApplicationTestBaseModule.cs** **add** the IdentityServer related using and PreConfigurations:
```csharp
using Volo.Abp.IdentityServer;
```
and
```csharp
PreConfigure(options =>
{
options.AddDeveloperSigningCredential = false;
});
PreConfigure(identityServerBuilder =>
{
identityServerBuilder.AddDeveloperSigningCredential(false, System.Guid.NewGuid().ToString());
});
```
to `PreConfigureServices` to run authentication related unit tests.
### UI Layer
You can follow the migrations guides from IdentityServer to OpenIddict in **reverse order** to update your UIs. You can also check the source-code for [Index.cshtml.cs](https://github.com/abpframework/abp-samples/blob/master/OpenId2Ids/src/OpenId2Ids.AuthServer/Pages/Index.cshtml) and [Index.cshtml](https://github.com/abpframework/abp-samples/blob/master/OpenId2Ids/src/OpenId2Ids.AuthServer/Pages/Index.cshtml.cs) files for **AuthServer** project.
- [Angular UI Migration](OpenIddict-Angular.md)
- [MVC/Razor UI Migration](OpenIddict-Mvc.md)
- [Blazor-Server UI Migration](OpenIddict-Blazor-Server.md)
- [Blazor-Wasm UI Migration](OpenIddict-Blazor.md)
## Source code of samples and module
* [Open source tiered & separate auth server application migrate OpenIddict to Identity Server](https://github.com/abpframework/abp-samples/tree/master/OpenId2Ids)
* [IdentityServer module document](https://docs.abp.io/en/abp/6.0/Modules/IdentityServer)
* [IdentityServer module source code](https://github.com/abpframework/abp/tree/rel-6.0/modules/identityserver)