Schedule Tasks is a built-in nopCommerce feature to automate some processes to run in background. It may be customer list synchronization with some 3rd party marketing software, product import from external source, database backup, or even simple processes such as log clearing and email sending.
In many cases, it will be enough to use an interval type (run every X minutes) used in nopCommerce schedule tasks. But sometimes, some advanced schedule is needed. For example:
With CRON Tasks plugin, it is possible to make even more complex task scheduling. It completely replaces a nopCommerce scheduling mechanism, improves it and makes it more flexible!
Free demo version is available with some CRON expression restrictions.
For documentation and details please refer to this link. You may also find a plugin for your older nopCommerce version there.