<PackageReference Include="Relativity.Server.ObjectManager.SDK" Version="1.1.2" />

MassUpdateOptions

public class MassUpdateOptions
Represents information about how a mass update request is performed by replacing or merging field values.
public FieldUpdateBehavior UpdateBehavior { get; set; }

Gets or set the behavior used when mass updating multiple choice and multiple object fields by replacing or merging values. By default, values are replaced.