public function validate_ipn() {
		WC_Gateway_Paypal::log( 'Checking IPN response is valid' );

		// Get received values from post data.
		$validate_ipn        = wp_unslash( $_POST ); // WPCS: CSRF ok, input var ok.
		$validate_ipn['cmd'] = '_notify-validate';

		// Send back post vars to paypal.
		$params = array(
			'body'        => $validate_ipn,
			'timeout'     => 60,
			'httpversion' => '1.1',
			'compress'    => false,
			'decompress'  => false,
			'user-agent'  => 'WooCommerce/' . WC()->version,
		);

		// Post back to get a response.
		$response = wp_safe_remote_post( $this->sandbox ? 'https://www.sandbox.paypal.com/cgi-bin/webscr' : 'https://www.paypal.com/cgi-bin/webscr', $params );

		WC_Gateway_Paypal::log( 'IPN Response: ' . wc_print_r( $response, true ) );

		// Check to see if the request was valid.
		if ( ! is_wp_error( $response ) && $response['response']['code'] >= 200 && $response['response']['code'] < 300 && strstr( $response['body'], 'VERIFIED' ) ) {
			WC_Gateway_Paypal::log( 'Received valid response from PayPal IPN' );
			return true;
		}

		WC_Gateway_Paypal::log( 'Received invalid response from PayPal IPN' );

		if ( is_wp_error( $response ) ) {
			WC_Gateway_Paypal::log( 'Error response: ' . $response->get_error_message() );
		}

		return false;
	}