phorge-phorge/resources/sql/patches/20130611.nukeldap.php

<?php

$table = new PhabricatorUser();
$conn = $table->establishConnection('w');
$table_name = 'user_ldapinfo';

foreach (new LiskRawMigrationIterator($conn, $table_name) as $row) {
  throw new Exception(
    pht(
      'This database has ancient LDAP account data and is too old to upgrade '.
      'directly to a modern version of the software. Upgrade to a version '.
      'released between June 2013 and February 2019 first, then upgrade to a '.
      'modern version.'));
}