diff --git a/library/Zend/Json.php b/library/Zend/Json.php
index 522e004..271d5c5 100644
--- a/library/Zend/Json.php
+++ b/library/Zend/Json.php
@@ -74,6 +74,11 @@ class Zend_Json
     public static function decode($encodedValue, $objectDecodeType = Zend_Json::TYPE_ARRAY)
     {
         $encodedValue = (string) $encodedValue;
+        // fix for php7 (empty strings result in syntax error for php >= 7.0.0 if calling json_last_error)
+        if (empty($encodedValue)) {
+            return null;
+        }
+
         if (function_exists('json_decode') && self::$useBuiltinEncoderDecoder !== true) {
             $decode = json_decode($encodedValue, $objectDecodeType);