Instead of creating a specific writer and then loading like
$objet = new PHPExcel_Reader_Excel5();
$xls = $objet->load('Providers.xls');
$objPHPExcel = PHPExcel_IOFactory::load('Providers.xls');
then PHPExcel will attempt to identify the file type (irrespective of the file extension) and use the appropriate reader for that file.
There is also an identify() method
$objPHPExcel = PHPExcel_IOFactory::identify('Providers.xls');
that uses the same identification logic as PHPExcel_IOFactory::load() and returns the name of the reader that should be instantiated to load the named file. The automatic identification logic isn't perfect, but it can help to avoid problems with misnamed
files in future.