# Sharing message assemblies


This sample shows how the `NServiceBus.MessageInterfaces` package can be used to create a shared message assembly that can be used by multiple major versions of NServiceBus, and in projects using different target frameworks, while still relying on the `ICommand` and `IEvent` marker interfaces.

In this sample, an NServiceBus endpoint running on .NET Framework can share a message assembly with another endpoint running a newer version of NServiceBus and .NET without the need to employ [unobtrusive message conventions](/nservicebus/messaging/unobtrusive-mode.md), which is especially useful for projects transitioning from .NET Framework to .NET that were not originally designed with message conventions in mind.

### Shared project

The `Shared` project references the `NServiceBus.MessageInterfaces`, which contains the definitions for `IMessage`, `ICommand`, and `IEvent`. Because this project targets `netstandard2.0` it can be used from both .NET and .NET Framework applications.

<!-- snippet: shared-project -->

```csproj
<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <LangVersion>12.0</LangVersion>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="NServiceBus.MessageInterfaces" Version="1.*" />
  </ItemGroup>

</Project>
```

<!-- endsnippet -->

There is a single message type defined, `MyCommand`, which derives from `ICommand`.

## Sending messages

The `Sender` endpoint uses NServiceBus 8.2 on .NET Framework and sends `MyCommand` messages to `Receiver`.

## Receiving messages

The `Receiver` endpoint uses NServiceBus 9 on modern .NET and has a handler for `MyCommand` messages.