What potential pitfalls should be considered when using Umlaut characters in Excel sheet names with PHPExcel?

When using Umlaut characters in Excel sheet names with PHPExcel, potential pitfalls to consider include compatibility issues with certain Excel versions or programs that may not support special characters in sheet names. To avoid these problems, it is recommended to stick to standard alphanumeric characters when naming sheets. If Umlaut characters must be used, ensure that the Excel version being used supports them.

$sheetName = 'Übersicht'; // Umlaut character in sheet name
$sheetName = iconv('UTF-8', 'ISO-8859-1//TRANSLIT', $sheetName); // Convert Umlaut character to ISO-8859-1
$objPHPExcel->getActiveSheet()->setTitle($sheetName); // Set the sheet name in PHPExcel