diff --git a/app/__init__.py b/app/__init__.py
index 4fc7569..b6b787d 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -103,6 +103,6 @@ def create_app():
 
     @app.template_filter("ts_datetime")
     def ts_datetime(ts, format):
-        return datetime.utcfromtimestamp(ts).strftime(format)
+        return datetime.utcfromtimestamp(ts or int(time.time())).strftime(format)
 
     return app