It was using the latest version of ADK it worked for LTSC 2019 and windows 10 21H1 but not for Windows 10 21H2.
I have just uninstalled the 2004 ADK and have installed the windows 11 ADK & PE files (updated my deplotment share)
Created a new standard client task sequence and selected the windows 10 Enterprise wim file.
Right Click Properties > OS info > Edit unattend.xml
the and get the following error
ERROR: Unable to generate catalog on D:\MDTDeployment\Operating Systems\Windows 10 Enterprise x64\Sources\install.wim: System.InvalidOperationException: The operation failed to complete. ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NotImplementedException: The method or operation is not implemented. blah blah
Click ok and get
Unable to edit the unattend.xml for this OS because no catalog could be located or generated.
So still not working. with the latest ADK
The reason I uninstalled the old WADKs to install the windows 11 ADKs and PE add=ons is because I found the following Microsoft documentation
A new Windows ADK is available for Windows 11 that also supports Windows 10, version 21H2.
Can anyone confirm that they have actually have this working ??