EE4 modify registration ID

modify_reg_id.php

<?php
// Please do NOT include the opening php tag, except of course if you're starting with a blank file


function change_reg_code($new_reg_code, $registration) {

  //create a new reg ID e.g. business-1598
  $new_reg_code = "business-" . rand(1000, 10000); 

  //send the new reg code back to be used.
  return $new_reg_code;
}
add_filter('FHEE__EE_Registration_Processor___generate_reg_code__new_reg_code','change_reg_code', 10, 2);






/*
*
*   This example will update a count for the registration code and keep it incremental
*   The event with need a Custom Field called count adding, with a value of 1
*
*   There is a flaw with this system in that as the registration ID is produced early on
*   if the registration is abandoned the count will still have been incremented.
*/
function change_reg_code($new_reg_code, $registration) {

    $eventid = $registration->event_ID();

    $count = get_post_meta( $eventid, 'count', true );

    //create a new reg ID e.g. business-count-1598
    $new_reg_code = "my_count-" . $count . '-' . rand(1000, 10000); 

    $newcount = (int)$count + 1;

    update_post_meta($eventid, 'count', $newcount, $count);

    //send the new reg code back to be used.
    return $new_reg_code;
}
add_filter('FHEE__EE_Registration_Processor___generate_reg_code__new_reg_code','change_reg_code', 10, 2);

Code was broken, fixed it. Also updated the filter hook as the original no longer exists.