diff --git a/src/include/class-wc-retailcrm-upload-discount-price.php b/src/include/class-wc-retailcrm-upload-discount-price.php
index c6973d6..c36101d 100644
--- a/src/include/class-wc-retailcrm-upload-discount-price.php
+++ b/src/include/class-wc-retailcrm-upload-discount-price.php
@@ -58,7 +58,12 @@ if (!class_exists('WC_Retailcrm_Upload_Discount_Price')):
                     ]
                 );
 
-                wp_cache_flush_runtime();
+                /** WP version >= 6 */
+                if (function_exists('wp_cache_flush_runtime')) {
+                    wp_cache_flush_runtime();
+                } else {
+                    wp_cache_flush();
+                }
 
                 if (empty($products)) {
                     writeBaseLogs('Can`t get products!');
@@ -147,7 +152,9 @@ if (!class_exists('WC_Retailcrm_Upload_Discount_Price')):
 
         private function uploadSettings()
         {
-            if (!$this->apiClient instanceof WC_Retailcrm_Proxy) {
+            if (!$this->apiClient instanceof WC_Retailcrm_Proxy
+                && !$this->apiClient instanceof WC_Retailcrm_Client_V5
+            ) {
                return 'API client has not been initialized';
             }
 
diff --git a/tests/datasets/data-upload-price-retailcrm.php b/tests/datasets/data-upload-price-retailcrm.php
new file mode 100644
index 0000000..3a5198c
--- /dev/null
+++ b/tests/datasets/data-upload-price-retailcrm.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace datasets;
+
+/**
+ * PHP version 7.0
+ *
+ * Class DataUploadPriceRetailCrm - Data set for WC_Retailcrm_Upload_Discount_Price_Test.
+ *
+ * @category Integration
+ * @author   RetailCRM <integration@retailcrm.ru>
+ * @license  http://retailcrm.ru Proprietary
+ * @link     http://retailcrm.ru
+ * @see      http://help.retailcrm.ru
+ */
+class DataUploadPriceRetailCrm
+{
+    public static function dataGetPriceTypes() {
+        return [
+            'success' => true,
+            'priceTypes' => [
+                [
+                    'code' => 'test',
+                    'name' => 'test',
+                    'active' => true,
+                    'description' => 'test',
+                    'ordering' => 999,
+                    'promo' => true,
+                    'default' => false
+                ],
+                [
+                    'code' => 'default',
+                    'name' => 'default',
+                    'active' => true,
+                    'description' => 'default',
+                    'ordering' => 999,
+                    'promo' => true,
+                    'default' => true
+                ],
+            ]
+        ];
+    }
+
+    public static function willSendPriceType() {
+        return [
+            'code' => 'woo-promotion-lp',
+            'name' => 'Woocommerce promotional price',
+            'active' => true,
+            'description' => 'Promotional price type for Woocommerce store, generated automatically.
+                     Necessary for correct synchronization work when loyalty program is enabled
+                      (Do not delete. Do not deactivate)',
+            'ordering' => 999,
+            'promo' => true,
+        ];
+    }
+}
diff --git a/tests/test-wc-retailcrm-upload-discount-price.php b/tests/test-wc-retailcrm-upload-discount-price.php
new file mode 100644
index 0000000..0d3894c
--- /dev/null
+++ b/tests/test-wc-retailcrm-upload-discount-price.php
@@ -0,0 +1,74 @@
+<?php
+
+use datasets\DataUploadPriceRetailCrm;
+
+/**
+ * PHP version 7.0
+ *
+ * WC_Retailcrm_Upload_Discount_Price_Test
+ *
+ * @category Integration
+ * @author   RetailCRM <integration@retailcrm.ru>
+ * @license  http://retailcrm.ru Proprietary
+ * @link     http://retailcrm.ru
+ * @see      http://help.retailcrm.ru
+ */
+class WC_Retailcrm_Upload_Discount_Price_Test extends WC_Retailcrm_Test_Case_Helper
+{
+    protected $apiMock;
+    protected $responseMock;
+
+    public function setUp()
+    {
+        WC_Helper_Product::create_simple_product();
+        WC_Helper_Product::create_variation_product();
+
+        $this->setOptions();
+
+        $this->responseMock = $this->getMockBuilder('\WC_Retailcrm_Response_Helper')
+            ->disableOriginalConstructor()
+            ->setMethods(['isSuccessful'])
+            ->getMock()
+        ;
+
+        $this->apiMock = $this->getMockBuilder('\WC_Retailcrm_Client_V5')
+            ->disableOriginalConstructor()
+            ->setMethods(['storePricesUpload', 'getSingleSiteForKey', 'getPriceTypes', 'editPriceType'])
+            ->getMock()
+        ;
+
+        $this->responseMock->setResponse(['success' => true]);
+        $this->setMockResponse($this->responseMock, 'isSuccessful', true);
+        $this->setMockResponse($this->apiMock, 'getSingleSiteForKey', 'woo');
+
+        $this->responseMock->setResponse(DataUploadPriceRetailCrm::dataGetPriceTypes());
+        $this->setMockResponse($this->apiMock, 'getPriceTypes', $this->responseMock);
+    }
+
+    public function testUpload()
+    {
+        $this->apiMock
+            ->expects($this->exactly(1))
+            ->method('storePricesUpload')
+            ->with($this->callback(
+                function ($parameter) {
+                    if (is_array($parameter)) {
+                        return true;
+                    }
+
+                    return false;
+                }
+            ), $this->equalTo('woo'))
+        ;
+
+        $this->apiMock
+            ->expects($this->exactly(1))
+            ->method('editPriceType')
+            ->with($this->identicalTo(DataUploadPriceRetailCrm::willSendPriceType()))
+            ->willReturn($this->responseMock)
+        ;
+
+        $uploadService = new WC_Retailcrm_Upload_Discount_Price($this->apiMock);
+        $uploadService->upload();
+    }
+}