diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index bb7b0c8..50207bc 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -39,4 +39,21 @@ require $plugin_dir . 'tests/helpers/class-wc-retailcrm-response-helper.php';
 require $plugin_dir . 'tests/helpers/class-wc-retailcrm-test-case-helper.php';
 require $plugin_dir . 'tests/helpers/class-wc-retailcrm-log-handler-stdout.php';
 
-WC_Retailcrm_Logger::setAdditionalHandlers(array(new WC_Retailcrm_Log_Handler_Stdout()));
\ No newline at end of file
+WC_Retailcrm_Logger::setAdditionalHandlers(array(new WC_Retailcrm_Log_Handler_Stdout()));
+
+/**
+ * Returns true if WP version is 4.6 or older. It's useful in some tests.
+ *
+ * @return bool
+ */
+function is_wp_older_or_4_6() {
+    include(ABSPATH . WPINC . '/version.php');
+
+    if (!empty($wp_version)) {
+        $version = explode('.', substr($wp_version, 0, 3));
+
+        return count($version) == 2 && ($version[0] > 4 || $version[1] > 6);
+    }
+
+    return true;
+}
diff --git a/tests/test-wc-retailcrm-history.php b/tests/test-wc-retailcrm-history.php
index 277701f..3ad9625 100644
--- a/tests/test-wc-retailcrm-history.php
+++ b/tests/test-wc-retailcrm-history.php
@@ -296,7 +296,10 @@ class WC_Retailcrm_History_Test extends WC_Retailcrm_Test_Case_Helper
         $this->assertEquals('Еврейская Автономная область', $order->get_billing_state());
         $this->assertEquals('Компания1', $order->get_billing_company());
         $this->assertEquals('9135487458709', $order->get_billing_phone());
-        $this->assertEmpty($order->get_customer_id());
+
+        if (!is_wp_older_or_4_6()) {
+            $this->assertEmpty($order->get_customer_id());
+        }
     }
 
     /**