diff --git a/Utils/JsonBuilder.php b/Utils/JsonBuilder.php
index 7c12126db..e447e6a7f 100644
--- a/Utils/JsonBuilder.php
+++ b/Utils/JsonBuilder.php
@@ -24,7 +24,7 @@ namespace phpOMS\Utils;
  * @link       http://orange-management.com
  * @since      1.0.0
  */
-class JsonBuilder implements \Serializable
+class JsonBuilder implements \Serializable, \JsonSerializable
 {
 
     /**
@@ -110,4 +110,9 @@ class JsonBuilder implements \Serializable
     {
         $this->json = json_decode($serialized);
     }
+
+    public function jsonSerialize()
+    {
+        return $this->json();
+    }
 }
diff --git a/Utils/StringUtils.php b/Utils/StringUtils.php
index 607726670..a0d175b0e 100644
--- a/Utils/StringUtils.php
+++ b/Utils/StringUtils.php
@@ -266,7 +266,7 @@ class StringUtils
      */
     public static function mb_trim(string $string, string $charlist = ' ') : string
     {
-        if (is_null($charlist)) {
+        if ($charlist === ' ') {
             return trim($string);
         } else {
             $charlist = str_replace('/', '\/', preg_quote($charlist));