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The module is a drop-in replacement for the default WHMCS reminder system. Thereforce you can use all default WHMCS mail variables.
Mail Template
Every reminder can use his own mail template. If you are using one template for all reminders, you can differ between the types using the {$reminder_type} variable (example can be found here).
Subject Variables
The subject can be totally customized at the module admin page.
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