diff --git a/application/bus/worldTime/currentTime.js b/application/bus/worldTime/currentTime.js
index abe5a945..77a8e6cb 100644
--- a/application/bus/worldTime/currentTime.js
+++ b/application/bus/worldTime/currentTime.js
@@ -16,9 +16,9 @@
     day_of_week: 'number',
     day_of_year: 'number',
     dst: 'boolean',
-    dst_from: 'string',
+    dst_from: '?string',
     dst_offset: 'number',
-    dst_until: 'string',
+    dst_until: '?string',
     raw_offset: 'number',
     timezone: 'string',
     unixtime: 'number',