diff --git a/app/views/Device.php b/app/views/Device.php
index c201367..9b790e8 100644
--- a/app/views/Device.php
+++ b/app/views/Device.php
@@ -57,7 +57,7 @@ class Device extends Template
if (!empty ($subdeviceLocal)) {
$devices[$key]['history'] = (!empty ($subdeviceLocal['history']) ? $subdeviceLocal['history'] : 0);
} else {
- unset($devices[$key]['history']);
+ $devices[$key]['history'] = "null";
}
$devices[$key]['signal'] = "";
if (!empty($subdevice['subdevice_id'])) {
diff --git a/app/views/templates/device.phtml b/app/views/templates/device.phtml
index 7f40c2c..4975c84 100644
--- a/app/views/templates/device.phtml
+++ b/app/views/templates/device.phtml
@@ -102,7 +102,7 @@