diff --git a/qubesmanager/qube_manager.py b/qubesmanager/qube_manager.py
index 395b8d1e..56a1f0d0 100644
--- a/qubesmanager/qube_manager.py
+++ b/qubesmanager/qube_manager.py
@@ -283,7 +283,7 @@ def update_power_state(self):
                     if datetime.now() > eol:
                         self.state['outdated'] = 'eol'
                 else:
-                    self.state['outdated'] = None
+                    self.state['outdated'] = ""
         except exc.QubesDaemonAccessError:
             pass