For upgrading any of your contributed Drupal 7 modules, you just need to follow the few steps shown below. First of all you have to make sure that Drush is installed. If not installed, follow the steps from here.
Module Upgrader
After the launch of Drupal 8, there is now an incessant need for converting existing Drupal 7 modules to Drupal 8 compatible versions. Due to the substantial changes in Drupal 8 from its previous versions, developers find it hard and time consuming to migrate from D7 to D8. This is mainly because Drupal 8 is object oriented and much closer to an MVC (Model View Controller) architecture, Drupal is no longer a PAC (Presentation Abstraction Control) architecture framework, Drupal follows the PSR-4 folder structure in compatible with symfony component which Drupal 8 uses.