Add more email Schedule options

add_filter('wplms_email_schedule','my_course_expiry_mail_settings');
function my_course_expiry_mail_settings($args){ 
    if(is_Array($args)){
        $args[7]['options']['2160'] = __('Before 3 month of Course expiry','vibe-customtypes');
    }       
    return $args;
}

2160 = number of hours in 3 months

 

for wplms 3.8 or above :

add_filter('wplms_course_expire_schedule_options',function ($settings){
  $settings['2160'] = __('Before 3 months of Course expiry','vibe-customtypes');
  return $settings;
});