diff --git a/doc/api/openapi/openapi_v2.yaml b/doc/api/openapi/openapi_v2.yaml
index 0719987e9e247107a1fe3373c7cfdc79c79e1076..298ebcd267cca53bb6f7fd2b89829ebc3e1013bc 100644
--- a/doc/api/openapi/openapi_v2.yaml
+++ b/doc/api/openapi/openapi_v2.yaml
@@ -38311,7 +38311,7 @@ paths:
       operationId: getApiV4MergeRequests
   "/api/v4/namespaces/{id}":
     put:
-      description: Update a namespace
+      description: "[DEPRECATED] Update a namespace"
       produces:
       - application/json
       consumes:
@@ -38329,7 +38329,7 @@ paths:
           "$ref": "#/definitions/putApiV4NamespacesId"
       responses:
         '200':
-          description: Update a namespace
+          description: "[DEPRECATED] Update a namespace"
           schema:
             "$ref": "#/definitions/API_Entities_Namespace"
       tags:
@@ -60963,7 +60963,7 @@ definitions:
             type: integer
             format: int32
             description: Whether subscription is an extended or reactivated trial
-    description: Update a namespace
+    description: "[DEPRECATED] Update a namespace"
   API_Entities_Namespace:
     type: object
     properties:
diff --git a/ee/lib/ee/api/namespaces.rb b/ee/lib/ee/api/namespaces.rb
index 883031b05cba4321449ab7d871a49045c7eed72e..326a6f27229edae2c8476eb91113f527a451da06 100644
--- a/ee/lib/ee/api/namespaces.rb
+++ b/ee/lib/ee/api/namespaces.rb
@@ -55,7 +55,7 @@ def update_namespace(namespace)
             end
           end
 
-          desc 'Update a namespace' do
+          desc '[DEPRECATED] Update a namespace' do
             success ::API::Entities::Namespace
           end
           params do