My custom validation broke with the upgrade. In the past, it seemed I was able to grab the value as it was before, and the new value submitted, so that I could determine if it was unique. Now, all I am getting in the $field variable is the new submitted value. How would I get the value that the field was before the change?

This was my previous validation formula:

add_filter('piklist_validation_rules', 'check_if_unique', 11);
function check_if_unique($validation_rules)
{
  $validation_rules['custom_unique'] = array(
	'type' => 'safe_text',
    'callback' => 'my_validate_unique'
  );
 
  return $validation_rules;
}
 
function my_validate_unique($file, $field, $arguments)
{

	$thereturned_field = $field['request_value'][0];
	 $duplicate_url = new WP_User_Query(  array(
	 'meta_key' => 'user_custom_url',
	 'meta_value' => $thereturned_field,
	 'exclude' => $field['attributes']['title']
	 ) );
	 $userscount = $duplicate_url->get_total();
	 //return($field['attributes']['title'] . " - total - " . $userscount . "search -" . $thereturned_field);
	 if($userscount == 0 )
  {
  return true;
  }else{
	  return __('is not unique and or used unsupported characters. ONLY letters and numbers.', 'Extreme');
  }
 
}