diff --git a/taiga/projects/custom_attributes/api.py b/taiga/projects/custom_attributes/api.py
index f87edf54..2a53d854 100644
--- a/taiga/projects/custom_attributes/api.py
+++ b/taiga/projects/custom_attributes/api.py
@@ -95,7 +95,7 @@ class TaskCustomAttributesValuesViewSet(BaseCustomAttributesValuesViewSet):
     model = models.TaskCustomAttributesValues
     serializer_class = serializers.TaskCustomAttributesValuesSerializer
     permission_classes = (permissions.TaskCustomAttributesValuesPermission,)
-    lockup_fields = "task_id"
+    lookup_field = "task_id"
     content_object = "task"
 
     def get_queryset(self):
@@ -108,7 +108,7 @@ class IssueCustomAttributesValuesViewSet(BaseCustomAttributesValuesViewSet):
     model = models.IssueCustomAttributesValues
     serializer_class = serializers.IssueCustomAttributesValuesSerializer
     permission_classes = (permissions.IssueCustomAttributesValuesPermission,)
-    lockup_fields = "issue_id"
+    lookup_field = "issue_id"
     content_object = "issue"
 
     def get_queryset(self):
diff --git a/tests/integration/resources_permissions/test_issues_custom_attributes_resource.py b/tests/integration/resources_permissions/test_issues_custom_attributes_resource.py
index 173f9b5f..e8e87048 100644
--- a/tests/integration/resources_permissions/test_issues_custom_attributes_resource.py
+++ b/tests/integration/resources_permissions/test_issues_custom_attributes_resource.py
@@ -317,9 +317,9 @@ def test_issue_custom_attribute_action_bulk_update_order(client, data):
 
 
 def test_issue_custom_attributes_values_retrieve(client, data):
-    public_url = reverse('issue-custom-attributes-values-detail', kwargs={"pk": data.public_issue.pk})
-    private_url1 = reverse('issue-custom-attributes-values-detail', kwargs={"pk": data.private_issue1.pk})
-    private_url2 = reverse('issue-custom-attributes-values-detail', kwargs={"pk": data.private_issue2.pk})
+    public_url = reverse('issue-custom-attributes-values-detail', kwargs={"issue_id": data.public_issue.pk})
+    private_url1 = reverse('issue-custom-attributes-values-detail', kwargs={"issue_id": data.private_issue1.pk})
+    private_url2 = reverse('issue-custom-attributes-values-detail', kwargs={"issue_id": data.private_issue2.pk})
 
     users = [
         None,
@@ -338,9 +338,9 @@ def test_issue_custom_attributes_values_retrieve(client, data):
 
 
 def test_issue_custom_attributes_values_update(client, data):
-    public_url = reverse('issue-custom-attributes-values-detail', kwargs={"pk": data.public_issue.pk})
-    private_url1 = reverse('issue-custom-attributes-values-detail', kwargs={"pk": data.private_issue1.pk})
-    private_url2 = reverse('issue-custom-attributes-values-detail', kwargs={"pk": data.private_issue2.pk})
+    public_url = reverse('issue-custom-attributes-values-detail', kwargs={"issue_id": data.public_issue.pk})
+    private_url1 = reverse('issue-custom-attributes-values-detail', kwargs={"issue_id": data.private_issue1.pk})
+    private_url2 = reverse('issue-custom-attributes-values-detail', kwargs={"issue_id": data.private_issue2.pk})
 
     users = [
         None,
@@ -370,9 +370,9 @@ def test_issue_custom_attributes_values_update(client, data):
 
 
 def test_issue_custom_attributes_values_patch(client, data):
-    public_url = reverse('issue-custom-attributes-values-detail', kwargs={"pk": data.public_issue.pk})
-    private_url1 = reverse('issue-custom-attributes-values-detail', kwargs={"pk": data.private_issue1.pk})
-    private_url2 = reverse('issue-custom-attributes-values-detail', kwargs={"pk": data.private_issue2.pk})
+    public_url = reverse('issue-custom-attributes-values-detail', kwargs={"issue_id": data.public_issue.pk})
+    private_url1 = reverse('issue-custom-attributes-values-detail', kwargs={"issue_id": data.private_issue1.pk})
+    private_url2 = reverse('issue-custom-attributes-values-detail', kwargs={"issue_id": data.private_issue2.pk})
 
     users = [
         None,
diff --git a/tests/integration/resources_permissions/test_tasks_custom_attributes_resource.py b/tests/integration/resources_permissions/test_tasks_custom_attributes_resource.py
index d45a3782..773c44cb 100644
--- a/tests/integration/resources_permissions/test_tasks_custom_attributes_resource.py
+++ b/tests/integration/resources_permissions/test_tasks_custom_attributes_resource.py
@@ -311,9 +311,9 @@ def test_task_custom_attribute_action_bulk_update_order(client, data):
 
 
 def test_task_custom_attributes_values_retrieve(client, data):
-    public_url = reverse('task-custom-attributes-values-detail', kwargs={"pk": data.public_task.pk})
-    private_url1 = reverse('task-custom-attributes-values-detail', kwargs={"pk": data.private_task1.pk})
-    private_url2 = reverse('task-custom-attributes-values-detail', kwargs={"pk": data.private_task2.pk})
+    public_url = reverse('task-custom-attributes-values-detail', kwargs={"task_id": data.public_task.pk})
+    private_url1 = reverse('task-custom-attributes-values-detail', kwargs={"task_id": data.private_task1.pk})
+    private_url2 = reverse('task-custom-attributes-values-detail', kwargs={"task_id": data.private_task2.pk})
 
     users = [
         None,
@@ -332,9 +332,9 @@ def test_task_custom_attributes_values_retrieve(client, data):
 
 
 def test_task_custom_attributes_values_update(client, data):
-    public_url = reverse('task-custom-attributes-values-detail', kwargs={"pk": data.public_task.pk})
-    private_url1 = reverse('task-custom-attributes-values-detail', kwargs={"pk": data.private_task1.pk})
-    private_url2 = reverse('task-custom-attributes-values-detail', kwargs={"pk": data.private_task2.pk})
+    public_url = reverse('task-custom-attributes-values-detail', kwargs={"task_id": data.public_task.pk})
+    private_url1 = reverse('task-custom-attributes-values-detail', kwargs={"task_id": data.private_task1.pk})
+    private_url2 = reverse('task-custom-attributes-values-detail', kwargs={"task_id": data.private_task2.pk})
 
     users = [
         None,
@@ -364,9 +364,9 @@ def test_task_custom_attributes_values_update(client, data):
 
 
 def test_task_custom_attributes_values_patch(client, data):
-    public_url = reverse('task-custom-attributes-values-detail', kwargs={"pk": data.public_task.pk})
-    private_url1 = reverse('task-custom-attributes-values-detail', kwargs={"pk": data.private_task1.pk})
-    private_url2 = reverse('task-custom-attributes-values-detail', kwargs={"pk": data.private_task2.pk})
+    public_url = reverse('task-custom-attributes-values-detail', kwargs={"task_id": data.public_task.pk})
+    private_url1 = reverse('task-custom-attributes-values-detail', kwargs={"task_id": data.private_task1.pk})
+    private_url2 = reverse('task-custom-attributes-values-detail', kwargs={"task_id": data.private_task2.pk})
 
     users = [
         None,