Since version 1.8.0, PHPExcel has offered an alternative built-in Zip handler that can be enabled by setting
PHPExcel_Settings::setZipClass(PHPExcel_Settings::PCLZIP);
before loading any files that are zip-based archives such as xlsx or ods
This is slower and uses more memory than PHP's own ZipArchive extension, but provides an alternative if ZipArchive isn't enabled