After V4 Migration - Site does not work


I followed all steps for v3 to v4 migration and after it gave the message migration done, the site wont start. Now SSH also does not work, I am able to login but no commands are giving any response except below :
PHP Parse error: syntax error, unexpected ‘list’ (T_LIST), expecting identifier (T_STRING) in phar:///usr/local/bin/ee/vendor/easyengine/auth-command/src/Auth_Command.php on line 657

pls help urgently