I am developing a class library based on the **NetStandard 2.0** framework for multiple platform compatibility sakes, and I need to serialize and deserialize objects. So I added a reference to the **Newtonsoft** library.

The problem is that I have the following exception at runtime:

> 
> System.IO.FileNotFoundException: 'Could not load file or assembly 'System.ComponentModel.Annotations, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.'
> 
> 
> 

I tried to manually add a reference to the **System.ComponentModel.Annotations version 4.2.0.0** but this version is not available.

**Is there a way to use Newtonsoft with NetStandard 2.0, or an alternative to perform serialization/deserialization operations?**

**Update: it seems that adding a reference to System.ComponentModel.Annotations" Version="4.4.1" and rebuilding the solution fixed the problem.**

**Here is the content of my csproj file:**

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

  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
  </PropertyGroup>

    <ItemGroup>
      <PackageReference Include="Newtonsoft.Json" Version="10.0.3" />
      <PackageReference Include="System.ComponentModel.Annotations" Version="4.4.1" />
    </ItemGroup>
</Project>

```