public function process_ipn( $posted ) {
		$posted = stripslashes_deep( $posted );

		if ( ! isset( $posted['tracking_id'] ) ) {
			exit;
		}

		// Extract the order ID.
		$order_id = intval( str_replace( $this->gateway()->invoice_prefix, '', $posted['tracking_id'] ) );

		if ( $this->debug ) {
			$this->log->add( $this->id, 'Checking IPN response for order #' . $order_id . '...' );
		}

		// Get the order data.
		$order = new WC_Order( $order_id );

		// Checks whether the invoice number matches the order.
		// If true processes the payment.
		if ( $order->id === $order_id ) {
			$status = esc_attr( $posted['status'] );

			if ( $this->debug ) {
				$this->log->add( $this->id, 'Payment status: ' . $status );
			}

			switch ( $status ) {
				case 'CANCELED' :
					$order->update_status( 'cancelled', __( 'Payment canceled via IPN.', 'woocommerce-gateway-paypal-adaptive-payments' ) );

					break;
				case 'CREATED' :
					$order->update_status( 'on-hold', __( 'The payment request was received. Funds will be transferred once the payment is approved.', 'woocommerce-gateway-paypal-adaptive-payments' ) );

					break;
				case 'COMPLETED' :
					// Check order not already completed.
					if ( $order->status == 'completed' ) {
						if ( $this->debug ) {
							$this->log->add( $this->id, 'Aborting, Order #' . $order->id . ' is already complete.' );
						}
						exit;
					}

					if ( ! empty( $posted['sender_email'] ) ) {
						update_post_meta( $order->id, 'Payer PayPal address', sanitize_text_field( $posted['sender_email'] ) );
					}

					$order->add_order_note( __( 'The payment was successful.', 'woocommerce-gateway-paypal-adaptive-payments' ) );
					$order->payment_complete();

					break;
				case 'INCOMPLETE' :
					$order->update_status( 'on-hold', __( 'Some transfers succeeded and some failed for a parallel payment or, for a delayed chained payment, secondary receivers have not been paid.', 'woocommerce-gateway-paypal-adaptive-payments' ) );

					break;
				case 'ERROR' :
					$order->update_status( 'failed', __( 'The payment failed and all attempted transfers failed or all completed transfers were successfully reversed.', 'woocommerce-gateway-paypal-adaptive-payments' ) );

					break;
				case 'REVERSALERROR' :
					$order->update_status( 'failed', __( 'One or more transfers failed when attempting to reverse a payment.', 'woocommerce-gateway-paypal-adaptive-payments' ) );

					break;
				case 'PROCESSING' :
					$order->update_status( 'on-hold', __( 'The payment is in progress.', 'woocommerce-gateway-paypal-adaptive-payments' ) );

					break;
				case 'PENDING' :
					$order->update_status( 'pending', __( 'The payment is awaiting processing.', 'woocommerce-gateway-paypal-adaptive-payments' ) );

					break;

				default :
					// No action.
					break;
			}
		} else {
			if ( $this->debug ) {
				$this->log->add( $this->id, 'Invalid IPN response for order #' . $order_id . '!' );
			}
		}
	}