Please follow the steps below to upgrade to version 18.104.22.168:
1- Login to your email.
2- Find the receipt email that you have received with a download link upon your purchase.
3- Download the latest release.
4- Navigate to your WordPress dashboard.
5- Go to "Plugins" » "Add New" page.
6- Click on the "Upload Plugin" button on top of the page.
7- Click on the "Choose File" button and select the plugin file you downloaded earlier to your computer.
8- Click on the "Install Now" button.
WordPress will automatically detect that you already have this plugin installed, and the new file contains a different version. It will then allow you to "Replace current with uploaded" version.