diff --git a/inc/class-wooviet-vnd-paypal-standard.php b/inc/class-wooviet-vnd-paypal-standard.php
index c87d277..075416a 100644
--- a/inc/class-wooviet-vnd-paypal-standard.php
+++ b/inc/class-wooviet-vnd-paypal-standard.php
@@ -25,8 +25,6 @@ class WooViet_VND_PayPal_Standard {
 	 */
 	protected $paypal_currency = 'USD';
 
-	//@todo - declare two vars 
-
 	/**
 	 * WooViet_VND_PayPal_Standard constructor.
 	 *
@@ -46,12 +44,11 @@ class WooViet_VND_PayPal_Standard {
 		// Add the exchange rate info for this gateway in the checkout page before proceeding in the PayPal pages
 		add_filter( 'option_woocommerce_paypal_settings', array( $this, 'add_exchange_rate_info' ), 11 );
 
-		// Match currency and amount between Paypal and WC Order
-		add_action( 'valid-paypal-standard-ipn-request', array( $this, 'match_order_currency_and_amount' ), 5 );
 
-		// Restore currency and amount for WC Order
-		add_action( 'valid-paypal-standard-ipn-request', array( $this, 'restore_order_currency_and_amount' ), 15 );
-		
+        // Remove checks on currency and gross (total) values
+		add_action( 'woocommerce_api_wc_gateway_paypal', array( $this, 'remove_currency_and_total_checks' ), 5 );
+
+
 	}
 
 	/**
@@ -116,79 +113,31 @@ class WooViet_VND_PayPal_Standard {
 		return $value;
 	}
 
-	/*	
-	* Match currency and amount from Paypal IPN with the order
-	* 
-	* Topic https://wordpress.org/support/topic/loi-order-bi-on-hold/
-	*
-	* @author 	htdat
-	* @since 	1.4.3
-	*/
-	public function match_order_currency_and_amount($posted) {
 
-		$order = ! empty( $posted['custom'] ) ? $this->get_paypal_order( $posted['custom'] ) : false;
+    /**
+     * Remove currency and total (gross) amount check in class WC_Gateway_Paypal_IPN_Handler
+     *
+     * @since 1.4.5
+     * @author htdat
+     */
+	public function remove_currency_and_total_checks() {
 
-		if ( $order ) {
-			$this->original_order_currency = $order->get_currency();
-			$this->original_order_total = $order->get_total();
+        // Remove these filters https://github.com/woocommerce/woocommerce/blob/3.7.1/includes/gateways/paypal/includes/class-wc-gateway-paypal-ipn-handler.php#L34-L35
+        remove_all_filters( 'woocommerce_api_wc_gateway_paypal', 10 );
+        remove_all_filters( 'valid-paypal-standard-ipn-request', 10 );
 
-			$order->set_currency( $posted['mc_currency'] );
-			$order->set_total( $posted['mc_gross'] );
+        // Get values for PayPal Standard settings
+        // Ref: https://github.com/woocommerce/woocommerce/blob/3.7.1/includes/gateways/paypal/class-wc-gateway-paypal.php#L58-L61
+        $paypal_options = get_option( 'woocommerce_paypal_settings' );
+        $testmode = 'yes' === $paypal_options['testmode'];
+        $receiver_email = is_null( $paypal_options['receiver_email'] ) ? $paypal_options['email'] : $paypal_options['receiver_email'];
 
-			$order->save();
-		}
+        // Replace it by a child class of WC_Gateway_Paypal_IPN_Handler,
+        // which overrides/removes validate_currency() and validate_amount()
+        require_once dirname(__FILE__) . '/paypal-standard/class-woo-viet-wc-gateway-paypal-ipn-handler.php.php';
+        $handler = new Woo_Viet_WC_Gateway_Paypal_IPN_Handler( $testmode, $receiver_email ); //@todo needs to handle the correct variables
+        $handler->check_response();
 
-	}
-
-	/*	
-	* Restore currency and amount of the order after the 'match_order_currency_and_amount' action
-	*
-	* @author 	htdat
-	* @since 	1.4.3
-	*/
-	public function restore_order_currency_and_amount($posted) {
-
-		$order = ! empty( $posted['custom'] ) ? $this->get_paypal_order( $posted['custom'] ) : false;
-
-		if ( $order ) {
-
-			$order->set_currency( $this->original_order_currency );
-			$order->set_total( $this->original_order_total );
-
-			$order->save();
-		}
-
-	}
-
-
-	/**
-	 * @see Grab this code from - can not call it directly https://github.com/woocommerce/woocommerce/blob/f5c2f89af6a9421af8edc2a4aa20d372e5be40f8/includes/gateways/paypal/includes/class-wc-gateway-paypal-response.php#L30 
-	 * 
-	 * @since 1.4.3 
-	 * @author htdat
-	 */
-	protected function get_paypal_order( $raw_custom ) {
-		// We have the data in the correct format, so get the order.
-		$custom = json_decode( $raw_custom );
-		if ( $custom && is_object( $custom ) ) {
-			$order_id  = $custom->order_id;
-			$order_key = $custom->order_key;
-		} else {
-			// Nothing was found.
-			WC_Gateway_Paypal::log( 'Order ID and key were not found in "custom".', 'error' );
-			return false;
-		}
-		$order = wc_get_order( $order_id );
-		if ( ! $order ) {
-			// We have an invalid $order_id, probably because invoice_prefix has changed.
-			$order_id = wc_get_order_id_by_order_key( $order_key );
-			$order    = wc_get_order( $order_id );
-		}
-		if ( ! $order || $order->get_order_key() !== $order_key ) {
-			WC_Gateway_Paypal::log( 'Order Keys do not match.', 'error' );
-			return false;
-		}
-		return $order;
-	}	
+    }
 
 }
\ No newline at end of file
diff --git a/inc/paypal-standard/class-woo-viet-wc-gateway-paypal-ipn-handler.php.php b/inc/paypal-standard/class-woo-viet-wc-gateway-paypal-ipn-handler.php.php
new file mode 100644
index 0000000..6a87209
--- /dev/null
+++ b/inc/paypal-standard/class-woo-viet-wc-gateway-paypal-ipn-handler.php.php
@@ -0,0 +1,20 @@
+<?php
+
+/**
+ * Override/remove two validate functions in the parent class
+ *
+ * @author   htdat
+ * @since    1.4.5
+ *
+ */
+if ( class_exists( 'WC_Gateway_Paypal_IPN_Handler' ) ) {
+
+	class Woo_Viet_WC_Gateway_Paypal_IPN_Handler extends WC_Gateway_Paypal_IPN_Handler {
+
+		protected function validate_currency( $order, $currency ) {}
+
+		protected function validate_amount( $order, $amount ) {}
+
+	}
+
+}
\ No newline at end of file