Fatal Error

Hello,

after update WordPress latest Version 4.9.6 when i activate the WP-Customer-Plugin, shows me:

Parse error: syntax error, unexpected ‘class’ (T_CLASS), expecting identifier (T_STRING) or variable (T_VARIABLE) or ‘{‘ or ‘$’ in /var/www/vhosts/-ideletethisdomainbecauseissecret-.info/httpdocs/service/wp-content/plugins/customer-area/src/php/core-addons/post-owner/helpers/post-owner-ajax-helper.class.php on line 67

can anyone help me please?

olli