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- Download the module archive from the client area and extract it.
- Upload the module to your WHMCS installation.
- Go to the WHMCS Admin backend, click on Setup → Addon Modules.
- Click Activate at Extended Domain Reminder.
- Click Configure, enter your License Key and select Full Administrator at Access Control.
After configurating the module disable the default WHMCS reminder mails by navigating to Setup → Automation Settings.