if don't mind you notification in admin panel, no need to null . You can fix editing functions.php in admin folder.
Delete this:
if (_CUSTOMER_ID == 'YOUR_CUSTOMER_ID' || _CUSTOMER_ID == 'YOUR_CUSTOMER_I' || _CUSTOMER_ID == '_CUSTOMER_ID')
{
$txt_notes[$i]['title'] = 'Critical Error';
$txt_notes[$i]['desc'] = 'The Customer ID in <strong>config.php</strong> is <strong>invalid</strong>. To use PHP Melody, update <strong>config.php</strong> with your real Customer ID which is available in your <a href="
https://www.phpsugar.com/customer/">Customer Account</a>.';
$txt_notes[$i]['ico'] = 'gritter-ico_warn.png';
$txt_notes[$i]['bgcolor'] = 'blue';
$i++;
}