diff --git a/Block/Adminhtml/Checks.php b/Block/Adminhtml/Checks.php
index eb3370b..a43ecd7 100644
--- a/Block/Adminhtml/Checks.php
+++ b/Block/Adminhtml/Checks.php
@@ -24,7 +24,7 @@ class Checks extends Template
     const STATUS_OK = 3;
 
     const PHP_MIN_VERSION = '7.0';
-    const MAGENTO_MIN_VERSION = '2.2.3';
+    const MAGENTO_MIN_VERSION = '2.1.17';
     const HUB_LATEST_VERSION_FILE =  'https://raw.githubusercontent.com/contactlab/magento2-hub/master/etc/module.xml';
 
     protected $_moduleResource;
diff --git a/Helper/Data.php b/Helper/Data.php
index 4c0a1c9..b183e9a 100644
--- a/Helper/Data.php
+++ b/Helper/Data.php
@@ -15,7 +15,6 @@
 use Magento\Catalog\Helper\Image as ImageHelper;
 use Magento\Framework\UrlInterface;
 use Magento\Catalog\Api\CategoryRepositoryInterface;
-use Magento\Framework\Serialize\Serializer\Json;
 
 
 class Data extends AbstractHelper
@@ -64,7 +63,6 @@ class Data extends AbstractHelper
     protected $_imageHelper;
     protected $_urlBuilder;
     protected $_categoryRepository;
-    protected $_serializer;
 
 
     public function __construct(
@@ -77,8 +75,7 @@ public function __construct(
         Address $address,
         ImageHelper $imageHelper,
         UrlInterface $urlBuilder,
-        CategoryRepositoryInterface $categoryRepository,
-        Json $serializer = null
+        CategoryRepositoryInterface $categoryRepository
 
     ) {
         $this->_resourceConfig = $resourceConfig;
@@ -90,8 +87,6 @@ public function __construct(
         $this->_imageHelper = $imageHelper;
         $this->_urlBuilder = $urlBuilder;
         $this->_categoryRepository = $categoryRepository;
-        $this->_serializer = $serializer ?: \Magento\Framework\App\ObjectManager::getInstance()
-            ->get(Json::class);
         parent::__construct($context);
 
     }
@@ -107,7 +102,7 @@ public function log($text)
         }
         return $this;
     }
-    
+
     protected function _isLogEnabled($storeId = null)
     {
         return (bool)$this->scopeConfig->getValue(self::CONTACTLAB_HUB_LOG_ENABLED,
@@ -233,7 +228,7 @@ public function getRemoteIpAddress($customerId = null)
 
 
     }
-    
+
     public function sendAbandonedCartToNotSubscribed($storeId = null)
     {
         return (bool)$this->scopeConfig->getValue(self::CONTACTLAB_HUB_ABANDONED_CART_TO_NOT_SUBSCRIBED,
@@ -394,11 +389,11 @@ public function getExternalId($customer)
     public function getCustomerExtraProperties($customer, $type = 'extended')
     {
         $extraProperties = array();
-        $attributesMap = $this->_serializer->unserialize($this->scopeConfig->getValue(
+        $attributesMap = json_decode($this->scopeConfig->getValue(
             self::CONTACTLAB_HUB_CUSTOMER_EXTRA_PROPERTIES_ATTRIBUTE_MAP,
             ScopeInterface::SCOPE_STORE,
             $customer->getStoreId()
-        ));
+        ), true);
         foreach ($attributesMap as $map)
         {
             if($type == $map['hub_type'])
@@ -499,7 +494,7 @@ public function getObjProduct($product)
             if($product->getImage())
             {
                 $productImage = $this->_urlBuilder->getBaseUrl(['_type' => UrlInterface::URL_TYPE_MEDIA])
-                . 'catalog/product' . $product->getImage();
+                    . 'catalog/product' . $product->getImage();
             }
             else
             {
diff --git a/Model/Adminhtml/System/Config/Backend/Map/Customer.php b/Model/Adminhtml/System/Config/Backend/Map/Customer.php
index be2d8f7..c5f8e9e 100644
--- a/Model/Adminhtml/System/Config/Backend/Map/Customer.php
+++ b/Model/Adminhtml/System/Config/Backend/Map/Customer.php
@@ -1,27 +1,4 @@
 <?php
-/*
-namespace Contactlab\Hub\Model\Adminhtml\System\Config\Backend\Map;
-
-class Customer extends \Magento\Config\Model\Config\Backend\Serialized
-{
-    const XML_PATH_HUB_FIELD_ATTRIBUTE = 'customer_mapping';
-
-
-    public function beforeSave()
-    {
-
-        $_value = $this->getValue();
-        unset($_value[static::XML_PATH_HUB_FIELD_ATTRIBUTE][-1]);
-        $startOne = array_combine(range(1, count($_value[static::XML_PATH_HUB_FIELD_ATTRIBUTE])),
-            array_values($_value[static::XML_PATH_HUB_FIELD_ATTRIBUTE]));
-        $_value[static::XML_PATH_HUB_FIELD_ATTRIBUTE] = $startOne;
-        $this->setValue($_value);
-
-        parent::beforeSave();
-    }
-}
-*/
-
 
 namespace Contactlab\Hub\Model\Adminhtml\System\Config\Backend\Map;
 
@@ -33,7 +10,6 @@ public function beforeSave()
 use Magento\Framework\Model\Context;
 use Magento\Framework\Model\ResourceModel\AbstractResource;
 use Magento\Framework\Registry;
-use Magento\Framework\Serialize\Serializer\Json;
 
 /**
  * Class CountryCreditCard
@@ -45,11 +21,6 @@ class Customer extends Value
      */
     protected $mathRandom;
 
-    /**
-     * @var \Magento\Framework\Serialize\Serializer\Json
-     */
-    private $serializer;
-
     /**
      * @param \Magento\Framework\Model\Context $context
      * @param \Magento\Framework\Registry $registry
@@ -59,7 +30,6 @@ class Customer extends Value
      * @param \Magento\Framework\Model\ResourceModel\AbstractResource $resource
      * @param \Magento\Framework\Data\Collection\AbstractDb $resourceCollection
      * @param array $data
-     * @param \Magento\Framework\Serialize\Serializer\Json $serializer
      */
     public function __construct(
         Context $context,
@@ -69,12 +39,9 @@ public function __construct(
         Random $mathRandom,
         AbstractResource $resource = null,
         AbstractDb $resourceCollection = null,
-        array $data = [],
-        Json $serializer = null
+        array $data = []
     ) {
         $this->mathRandom = $mathRandom;
-        $this->serializer = $serializer ?: \Magento\Framework\App\ObjectManager::getInstance()
-            ->get(Json::class);
         parent::__construct($context, $registry, $config, $cacheTypeList, $resource, $resourceCollection, $data);
     }
 
@@ -90,7 +57,7 @@ public function beforeSave()
         {
             unset($value['__empty']);
         }
-        $this->setValue($this->serializer->serialize($value));
+        $this->setValue(json_encode($value));
         return $this;
     }
 
@@ -102,7 +69,7 @@ public function beforeSave()
     public function afterLoad()
     {
         if ($this->getValue()) {
-            $value = $this->serializer->unserialize($this->getValue());
+            $value = json_decode($this->getValue(), true);
             if (is_array($value)) {
                 $this->setValue($value);
             }
diff --git a/composer.json b/composer.json
index 9a93164..c23ba73 100644
--- a/composer.json
+++ b/composer.json
@@ -9,7 +9,7 @@
 
     },
     "type": "magento2-module",
-    "version": "1.6.0",
+    "version": "1.7.0",
     "license": [
         "OSL-3.0",
         "AFL-3.0"
diff --git a/etc/module.xml b/etc/module.xml
index 188f48d..f3af385 100644
--- a/etc/module.xml
+++ b/etc/module.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
-    <module name="Contactlab_Hub" setup_version="1.6.0">
+    <module name="Contactlab_Hub" setup_version="1.7.0">
         <sequence>
             <module name="Contactlab_Core"/>
         </sequence>