Announcing the deprecation of the WIT and Test Client OM

Dan Hellem

Updated contents on April 2, 2019

Since the first version of Team Foundation Server (TFS) in 2005, we have provided a set of SOAP APIs for programmatic interaction with Work Items and Tests. In recent years, REST has replaced SOAP as the preferred method for building integrations offering a simpler and more flexible programming model, support for multiple data formats, and superior performance and scalability. As our REST APIs have matured we’ve reached a point where we feel it’s time to announce the deprecation of the Work Item and Test SOAP APIs.

Starting in Visual Studio 2019 and Azure DevOps Server 2019, all work item and test methods in the Microsoft.TeamFoundationServer.ExtendedClient are marked as obsolete. Our ExtendedClient nuget package will also be updated with the obsolete attributes.

It is important to note that current functionality in the WIT Client will not change and is still supported as is. However, we will not be investing in the WIT Client OM as new Azure Boards and Azure Test features are released.

If you are a consumer of these SOAP APIs we recommend to plan for a migration to REST. The table below outlines a deprecation matrix of what you can expect across both SOAP and REST.

Azure DevOps Server

TFS 2018 Server 2019 Server 2020+
SOAP WIT Yes Deprecated Deprecated
Test Yes Deprecated Deprecated
REST WIT Yes Yes Yes
Test Partial Yes Yes

Azure DevOps Service

Starting in 2019
SOAP WIT Deprecated
Test Deprecated
Test Yes

Additional resources

If you need help, or want to provide feedback, please reach out to this support alias.


What does deprecation mean?

This means that any new features for Azure Boards or Azure Test will not be added into the Client OM. New functionality will only be supported in the REST APIs

What happens to the Version Control SDK and its SOAP APIs?

We will keep supporting the Version Control SDK, but we will end-of-life the SDK at some point in the future. If you create a new application, we recommend you start with the REST APIs. If you have existing apps using the SOAP SDK, we recommend you migrate to the REST APIs.

The SDK included an easy-to-use C# client library. Does REST API have an equivalent?

Yes, the REST APIs have a .NET library that abstract out the need to call REST APIs directly.

I’m using TFS2017 or an earlier version. Can I migrate to REST APIs?

No, older versions of TFS don’t include the full set of Work Items and Test REST APIs

Which assemblies are impacted?


Which NuGet package is impacted?

These assemblies are part of the Microsoft.TeamFoundationServer.ExtendedClient NuGet Package. Please be aware that this package not only contains WIT assemblies, but also provide support for Build and Code. We will keep supporting the Build and Code assemblies. Only the WIT and Test assemblies are marked as deprecated


Discussion is closed. Login to edit/delete existing comments.

  • Levai, Krisztian (IOT DS EU HU OPS 5 ALM 4) 0


    Does this mean that the exisiting features of Visual Studio Team Explorer Work Item handling will still work with Azure DevOps Server 2019 and 2020? For Example, could I still use VS 2017 to connect to an Azure DevOps Server 2019 and display work items inside VS itself?

    The reason this matters for our company is that we have created a huge amount of extensions for VS TE that are not yet remade for WebAccess.

    Best regards,

    • StavroulaSsi 0

      Hi Krisztian,
      did the API still worked for you with Azure DevOps Server 2019?
      Best regards,

Feedback usabilla icon