diff --git a/src/Controller/SystemStatusController.php b/src/Controller/SystemStatusController.php
index 768ed80..161c308 100644
--- a/src/Controller/SystemStatusController.php
+++ b/src/Controller/SystemStatusController.php
@@ -116,6 +116,10 @@ class SystemStatusController extends ControllerBase {
       $filename = $theme->getPath() . '/' . $theme->getFilename();
       $theme_info = Yaml::decode(file_get_contents($filename));
 
+      if (!isset($theme_info['version'])) {
+        $theme_info['version'] = NULL;
+      }
+
       // this can happen when you install using composer
       if($theme_info['version'] == "VERSION") {
           $theme_info['version'] = \Drupal::VERSION;