What are common issues with PHP upload scripts when transferring to a new server?

Common issues with PHP upload scripts when transferring to a new server include file permission errors, incorrect file paths, and outdated PHP configurations. To solve these issues, ensure that the file upload directory has the correct permissions set, update any file paths to match the new server's directory structure, and check if the PHP configuration allows file uploads.

// Example code to set correct file permissions for the upload directory
$upload_dir = 'uploads/';
if (!file_exists($upload_dir)) {
    mkdir($upload_dir, 0777, true);
}