Let's see how to update your Drupal site between 8.x.x minor and patch versions. For example, from 8.1.2 to 8.1.3, or from 8.3.5 to 8.4.0. I hope this will help you.
Drupal cron queue is very useful while running a big cron job. It will split a big cron job into small chunks and execute without getting timed out or being abruptly ended.
Drupal has a rich set of API to aid us in implementing custom functionalities with minimal optimized code. One such utility is system_settings_form($form).