function get_custom_email_html( $order, $heading = false, $mailer ) {

	$template = 'emails/my-custom-email-i-want-to-send.php';

	return wc_get_template_html( $template, array(
		'order'         => $order,
		'email_heading' => $heading,
		'sent_to_admin' => false,
		'plain_text'    => false,
		'email'         => $mailer
	) );

}

// load the mailer class
$mailer = WC()->mailer();

//format the email
$recipient = "someone@somewhere.com";
$subject = __("Hi! Here is a custom notification from us!", 'theme_name');
$content = get_custom_email_html( $order, $subject, $mailer );
$headers = "Content-Type: text/html\r\n";

//send the email through wordpress
$mailer->send( $recipient, $subject, $content, $headers );

function wpb_stop_update_emails( $send, $type, $core_update, $result ) {
	if ( ! empty( $type ) && $type == 'success' ) {
		return false;
	}
	return true;
}
add_filter( 'auto_core_update_send_email', 'wpb_stop_auto_update_emails', 10, 4 );