diff --git a/cluster_upgrade/handlers.py b/cluster_upgrade/handlers.py
index 4f61f2e..9a89a61 100644
--- a/cluster_upgrade/handlers.py
+++ b/cluster_upgrade/handlers.py
@@ -29,7 +29,9 @@ class ClusterUpgradeCloneHandler(base.BaseHandler):
     single = objects.Cluster
     validator = validators.ClusterUpgradeValidator
 
-    @base.content
+    @base.handle_errors
+    @base.validate
+    @base.serialize
     def POST(self, cluster_id):
         """Initialize the upgrade of the cluster.
 
@@ -50,7 +52,7 @@ class ClusterUpgradeCloneHandler(base.BaseHandler):
         request_data = self.checked_data(cluster=orig_cluster)
         new_cluster = upgrade.UpgradeHelper.clone_cluster(orig_cluster,
                                                           request_data)
-        return new_cluster.to_json()
+        return new_cluster.to_dict()
 
 
 class NodeReassignHandler(base.BaseHandler):
@@ -67,7 +69,8 @@ class NodeReassignHandler(base.BaseHandler):
 
         self.raise_task(task)
 
-    @base.content
+    @base.handle_errors
+    @base.validate
     def POST(self, cluster_id):
         """Reassign node to the given cluster.
 
@@ -107,7 +110,8 @@ class CopyVIPsHandler(base.BaseHandler):
     single = objects.Cluster
     validator = validators.CopyVIPsValidator
 
-    @base.content
+    @base.handle_errors
+    @base.validate
     def POST(self, cluster_id):
         """Copy VIPs from original cluster to new one
 
diff --git a/cluster_upgrade/objects/adapters.py b/cluster_upgrade/objects/adapters.py
index 3348229..cf4751b 100644
--- a/cluster_upgrade/objects/adapters.py
+++ b/cluster_upgrade/objects/adapters.py
@@ -74,8 +74,8 @@ class NailgunClusterAdapter(object):
             instance=self.cluster)
         return NailgunNetworkManager(self.cluster, net_manager)
 
-    def to_json(self):
-        return objects.Cluster.to_json(self.cluster)
+    def to_dict(self):
+        return objects.Cluster.to_dict(self.cluster)
 
     @classmethod
     def get_by_uid(cls, cluster_id):