Description:
------------
Hi, I suggest to create in the next php versions a function similar to 
array_change_key_case() but doing it recursevely. Bellow I put some example to doing that and the results.

regards, Luis

Test script:
---------------
<?php

    function arrKey2Lower(&$arrVals) {
        foreach( $arrVals as $key => $item ) {
            $key2 = strtolower($key);
            if ( $key2 != $key) {
                unset($arrVals[$key]);
                $arrVals[$key2]=$item;
                $key=$key2;
            }
            
            if ( is_array($item) ) { arrKey2Lower($arrValores[$key]); }
        }
    }
    
    $arr = array('ID' => 1, 'NAME'=> 'Luis', 'Contact' => array('PHONE' => '3010-7148', 'E-MAIL' => 'luis@net.com') );
    arrKey2Lower($arr);
    var_dump($arr);
    
    
?>

Expected result:
----------------
array(3) {
  ["id"]=>
  int(1)
  ["name"]=>
  string(4) "Luis"
  ["contact"]=>
  array(2) {
    ["phone"]=>
    string(9) "3010-7148"
    ["e-mail"]=>
    string(12) "luis@net.com"
  }
}