Help:Installation/Troubleshooting/Parse error: syntax error, unexpected

'''Parse error: syntax error, unexpected '?' in ... "update.php" on a PHP 7.x system'''

This means that you use PHP 5.6 as a command line default and try to run "update.php". The version check for PHP will not help you in giving useful feedback as you will receive a syntax error. CiteRef::gh:smw:4148

→ To resolve this you have to make sure that command line also uses PHP 7.x. Check back with your web hosting provider to make sure.