diff --git a/src/ReportPortal.Client/Abstractions/Requests/AssignTestItemIssuesRequest.cs b/src/ReportPortal.Client/Abstractions/Requests/AssignTestItemIssuesRequest.cs
index 1461be75..7ecd0009 100644
--- a/src/ReportPortal.Client/Abstractions/Requests/AssignTestItemIssuesRequest.cs
+++ b/src/ReportPortal.Client/Abstractions/Requests/AssignTestItemIssuesRequest.cs
@@ -1,35 +1,29 @@
 using ReportPortal.Client.Abstractions.Responses;
 using System.Collections.Generic;
-using System.Runtime.Serialization;
 
 namespace ReportPortal.Client.Abstractions.Requests
 {
     /// <summary>
     /// Defines a request for assigning issues to test items.
     /// </summary>
-    [DataContract]
     public class AssignTestItemIssuesRequest
     {
         /// <summary>
         /// List of test items and their issues.
         /// </summary>
-        [DataMember(Name = "issues")]
         public List<TestItemIssueUpdate> Issues { get; set; }
     }
 
-    [DataContract]
     public class TestItemIssueUpdate
     {
         /// <summary>
         /// A issue of test item.
         /// </summary>
-        [DataMember(Name = "issue")]
         public Issue Issue { get; set; }
 
         /// <summary>
         /// ID of test item to assign the issue.
         /// </summary>
-        [DataMember(Name = "testItemId")]
         public long TestItemId { get; set; }
     }
 }
diff --git a/src/ReportPortal.Client/Abstractions/Responses/Project/PreferenceResponse.cs b/src/ReportPortal.Client/Abstractions/Responses/Project/PreferenceResponse.cs
index a840cc09..2c6b2e43 100644
--- a/src/ReportPortal.Client/Abstractions/Responses/Project/PreferenceResponse.cs
+++ b/src/ReportPortal.Client/Abstractions/Responses/Project/PreferenceResponse.cs
@@ -1,21 +1,16 @@
 using System.Collections.Generic;
-using System.Runtime.Serialization;
 
 namespace ReportPortal.Client.Abstractions.Responses.Project
 {
-    [DataContract]
     public class PreferenceResponse
     {
         /// <summary>
         /// List of filters in a preference.
         /// </summary>
-        [DataMember(Name = "filters")]
         public IList<UserFilterResponse> Filters { get; set; }
 
-        [DataMember(Name = "projectId")]
         public long ProjectId { get; set; }
 
-        [DataMember(Name = "userId")]
         public long UserId { get; set; }
     }
 }
diff --git a/src/ReportPortal.Client/Abstractions/Responses/Project/ProjectDefectSubType.cs b/src/ReportPortal.Client/Abstractions/Responses/Project/ProjectDefectSubType.cs
index 3d682c90..ee9d617f 100644
--- a/src/ReportPortal.Client/Abstractions/Responses/Project/ProjectDefectSubType.cs
+++ b/src/ReportPortal.Client/Abstractions/Responses/Project/ProjectDefectSubType.cs
@@ -1,23 +1,15 @@
-using System.Runtime.Serialization;
-
-namespace ReportPortal.Client.Abstractions.Responses.Project
+namespace ReportPortal.Client.Abstractions.Responses.Project
 {
-    [DataContract]
     public class ProjectDefectSubType
     {
-        [DataMember(Name = "id")]
         public long Id { get; set; }
 
-        [DataMember(Name = "color")]
         public string Color { get; set; }
 
-        [DataMember(Name = "locator")]
         public string Locator { get; set; }
 
-        [DataMember(Name = "longName")]
         public string LongName { get; set; }
 
-        [DataMember(Name = "shortName")]
         public string ShortName { get; set; }
     }
 }