According to the PhpSpreadsheet Doc it\'s neccessary to install it with composer. In my case I just have a webspace without Terminal but Plesk. Is it anyway possible to use
Smartpal, thanks for your pack, it works fine!
Also it possible to replace folder:
/phpspreadsheet/vendor/phpoffice/phpspreadsheet/src/
in Smartpal's archive with more fresh sources from phpspreadsheet github and it also will work.
PS: If you have issues with reading xls files saved in encoding other than CP1252, you have to seek literals CP1252 in file ./src/PhpSpreadsheet/Reader/Xls.php and replace them with other value that you need or some named constant or even mb_detect_encoding(). Then it will read such xls correctly.