The Amazon SDK for .NET V3 has entered maintenance mode.

We recommend that you migrate to [Amazon SDK for .NET V4](https://docs.amazonaws.cn/sdk-for-net/v4/developer-guide/welcome.html). For additional details and information on how to migrate, please refer to our [maintenance mode announcement](https://aws.amazon.com/blogs/developer/aws-sdk-for-net-v3-maintenance-mode-announcement/).

# Special considerations for Unity support
<a name="unity-special"></a>

When using the Amazon SDK for .NET and [.NET Standard 2.0](https://docs.microsoft.com/en-us/dotnet/standard/net-standard) for your Unity application, your application must reference the Amazon SDK for .NET assemblies (DLL files) directly rather than using NuGet. Given this requirement, the following are important actions you will need to perform.


+ You need to obtain the Amazon SDK for .NET assemblies and apply them to your project. For information about how to do this, see [Download and extract ZIP files](net-dg-obtain-assemblies.md#download-zip-files) in the topic [Obtaining AWSSDK assemblies](net-dg-obtain-assemblies.md).
+ You need to include the following DLLs in your Unity project alongside the DLLs for **AWSSDK.Core** and the other Amazon services you're using. Starting with version 3.5.109 of the Amazon SDK for .NET, the .NET Standard ZIP file contains these additional DLLs.
  + [Microsoft.Bcl.AsyncInterfaces.dll](https://www.nuget.org/packages/Microsoft.Bcl.AsyncInterfaces/)
  + [System.Runtime.CompilerServices.Unsafe.dll](https://www.nuget.org/packages/System.Runtime.CompilerServices.Unsafe/)
  + [System.Threading.Tasks.Extensions.dll](https://www.nuget.org/packages/System.Threading.Tasks.Extensions/)
+ If you're using [IL2CPP](https://docs.unity3d.com/Manual/IL2CPP.html) to build your Unity project, you must add a `link.xml` file to your Asset folder to prevent code stripping. The `link.xml` file must list all of the AWSSDK assemblies you are using, and each must include the `preserve="all"` attribute. The following snippet shows an example of this file.

  ```
  <linker>
      <assembly fullname="AWSSDK.Core" preserve="all"/>
      <assembly fullname="AWSSDK.DynamoDBv2" preserve="all"/>
      <assembly fullname="AWSSDK.Lambda" preserve="all"/>
  </linker>
  ```

**Note**  
To read interesting background information related to this requirement, see the article at [https://amazonaws-china.com/blogs/developer/referencing-the-aws-sdk-for-net-standard-2-0-from-unity-xamarin-or-uwp/](https://amazonaws-china.com/blogs/developer/referencing-the-aws-sdk-for-net-standard-2-0-from-unity-xamarin-or-uwp/).

In addition to these special considerations, see [What's changed for version 3.5](net-dg-v35.md#net-dg-v35-changes) for information about migrating your Unity application to version 3.5 of the Amazon SDK for .NET.