Update confirmation_email method

Hello

First of all, thank you so much for this plugin. I find it very useful. However, there is several issue with this plugin. Mostly when doing checkout. As far as i can check, you guys hooked to the ‘woocommerce_checkout_update_order_meta’ action for generating email and also invoice URL via confirmation_email method. But looks like you guys write incorrect method to call WooCommerce order object. For example, instead using $order->get_id() you guys using $order->id. And it’s throwing some notice https://prntscr.com/s7fb2f . So for next update, please fix this issue. Thank you in advance.