# Gateway Upgrade Version 2 to 3


## Code-first API

The gateway now allows full configuration via code. To enable the gateway and configure sites and channels:

```csharp
endpointConfiguration.Gateway(new InMemoryDeduplicationConfiguration());
```

The above code replaces the previous method of configuring the gateway so the following should no longer be used: 

```csharp
endpointConfiguration.EnableFeature<Gateway>();
```

## Configuration

When running on .NET Core, options in configuration files are **not automatically detected**. Use the code-first API instead.

When running on the .NET Framework, settings in configuration files will still be used. However a warning will be logged indicating that it should be explicitly configured using the code-first API instead.