PHP Warnings

Hi. Due to outdated code like line 390 of class-wc-gateway-inspire:

$base_request = array (
	'ccnumber'	=> $this->get_post( 'ccnum' ),
	'cvv'		=> $this->get_post( 'cvv' ),
	'ccexp'		=> $expmonth . $expyear,
	'firstname'	=> $order->billing_first_name,
	'lastname'	=> $order->billing_last_name,
	'address1'	=> $order->billing_address_1,
	'city'		=> $order->billing_city,
	'state'		=> $order->billing_state,
	'zip'		=> $order->billing_postcode,
	'country'	=> $order->billing_country,
	'phone'		=> $order->billing_phone,
	'email'		=> $order->billing_email,
);

…the following fills the PHP error log when an order is placed:

[25-Feb-2019 17:16:39 UTC] billing_first_name was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:39 UTC] billing_last_name was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:39 UTC] billing_address_1 was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:39 UTC] billing_city was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:39 UTC] billing_state was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:39 UTC] billing_postcode was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:39 UTC] billing_country was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:39 UTC] billing_phone was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:39 UTC] billing_email was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:39 UTC] order_total was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:41 UTC] id was called incorrectly. Product properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Order->payment_complete, WC_Order->save, WC_Order->status_transition, do_action('woocommerce_order_status_pending_to_processing'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Emails::send_transactional_email, do_action_ref_array('woocommerce_order_status_pending_to_processing_notification'), WP_Hook->do_action, WP_Hook->apply_filters, WC_Email_New_Order->trigger, WC_Email->get_recipient, apply_filters('woocommerce_email_recipient_new_order'), WP_Hook->apply_filters, my_woocommerce_email_recipient_new_order, WC_Abstract_Legacy_Product->__get, wc_doing_it_wrong. This message was added in version 3.0.
[25-Feb-2019 17:16:42 UTC] id was called incorrectly. Order properties should not be accessed directly. Backtrace: require('wp-blog-header.php'), require_once('wp-includes/template-loader.php'), do_action('template_redirect'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::do_wc_ajax, do_action('wc_ajax_checkout'), WP_Hook->do_action, WP_Hook->apply_filters, WC_AJAX::checkout, WC_Checkout->process_checkout, WC_Checkout->process_order_payment, WC_Gateway_Inspire->process_payment, WC_Abstract_Legacy_Order->__get, wc_doing_it_wrong. This message was added in version 3.0.

For example,

$order->billing_first_name

should now be:

$order->get_billing_first_name()

Let me know if you plan to fix this or if I should seek a plugin/gateway that is more actively maintained. Thanks!