unexpected '?', expecting variable (T_VARIABLE)

[muuvmuuv]

I recently deployed a wordpress project on our debian based system and this is what I get:

Parse error: syntax error, unexpected '?', expecting variable (T_VARIABLE) in /srv/var/apache/vhosts/XXX/wp-content/themes/additive/vendor/lodash-php/lodash-php/src/internal/arrayIncludes.php on line 16

php --version:

PHP 7.0.30-0+deb9u1 (cli) (built: Jun 14 2018 13:50:25) ( NTS )
Copyright (c) 1997-2017 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2017 Zend Technologies
    with Zend OPcache v7.0.30-0+deb9u1, Copyright (c) 1999-2017, by Zend Technologies

I'm just using one piece of PHP Lodash use function _\find; which is implemented here:

$response = find($object, function ($o) use ($search) {
      return strtolower($search) == strtolower($o->name);
    });

[pierredup]

@muuvmuuv Lodash-PHP requires PHP 7.1 since it makes use of nullable types which was only introduced in PHP 7.1

[muuvmuuv]

Ah okay, thanks! Searched the web for the name of "nullable types" to find out if it is just PHP version. Thanks!