Trying to upgrade OJS from 126.96.36.199 to 188.8.131.52 (PHP 7.0.29, Apache 2.2.22, mysql 5.5.60).
I update through the command line and get the following error:
PHP Parse error: syntax error, unexpected '?', expecting variable (T_VARIABLE) in ***/lib/pkp/classes/notification/PKPNotificationOperationManager.inc.php on line 373
There are no additional errors in php-error logs, only the same line.
What is the reason and how to solve the update problem?