When I compared the files, I saw admin/includes/functions/general.php has two lines with strtolower command. My cart is multilanguage that includes english, traditional chinese and simplified chinese and in utf-8 format.
Is strtolower or strtoupper command compatible for charset in utf-8? I am afraid the wrong code will appear.
If the command are not compatible for utf-8 codes, can I delete this command wherever it appeared?