Filter to modify the days prior to renewal that the Recurring Payment Email Reminders Add On sends members the membership_recurring email notifcation.

custom_pmpro_upcoming_recurring_payment_reminder.php

<?php
/**
  * Filter to modify the days prior to renewal that the Recurring Payment Email Reminders Add On
  * sends members the membership_recurring email notifcation.
  *
  * Add this code below to your PMPro Customizations Plugin - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
  */
function custom_pmpro_upcoming_recurring_payment_reminder( $rec_array ) {
     $rec_array = array( 30 => 'membership_recurring', );
     return $rec_array;
}
add_filter('pmpro_upcoming_recurring_payment_reminder', 'custom_pmpro_upcoming_recurring_payment_reminder', 10, 1);