Convert bbPress 1 favorite topics into topic subscriptions in bbPress 2

bbpress-subscribers-convert.php

<?php

include('wp-load.php');

global $wpdb;
$aUsers = $wpdb->get_results("SELECT user_id,meta_value FROM $wpdb->usermeta WHERE meta_key = 'bb_favorites'");
$i = 0;

foreach($aUsers as $user){
    
  $i++;
  $sTopics = $user->meta_value;
  $aTopics = explode(',',$sTopics);
  $sUser_name = $wpdb->get_col("SELECT user_login FROM $wpdb->users WHERE ID=$user->user_id");
  echo "USER: ".$sUser_name[0]." (".$user->user_id.")</br>";
  $sSubscriptions = "";
  
  foreach($aTopics as $sOld_topic_id){
    echo "Old topic id :".$sOld_topic_id."</br>";
    if(strlen($sOld_topic_id)>0){            
      $sTopic_id = $wpdb->get_col("SELECT post_id FROM $wpdb->postmeta WHERE meta_value = $sOld_topic_id AND meta_key='_bbp_old_topic_id'");
      $sSubscriptions .= $sTopic_id[0].",";
    }  
  }
  
  $sSubscriptions = trim($sSubscriptions,",");
  echo "NEW SUBSCRIPTIONS: ".$sSubscriptions."</br>";

  $res = add_user_meta($user->user_id, "wp__bbp_subscriptions", $sSubscriptions );
  
  if($res == false){
      echo "META KEY WASN'T INSRETED!</br>";
  } else{
      echo "META KEY WAS INSERTED!</br>";
  }
    

}

echo "SUBSCRIPTIONS FOR $i USERS WERE UPDATED FROM bb_favorites TO wp__bbp_subscriptions</br>";