Since upgrading to WordPress 5.0 activating the plugin results in a fatal error. Activating either the free or pro versions of the plugin result in a fatal error which crashes the admin screen and forces me to delete the plugin via FTP in order to regain access to my site.

Looking at the error logs, the error triggered is as follows. Would it be possible to advise how I can continue using the plugin and avoid this issue?

2018-12-10T17:38:05+00:00 CRITICAL Uncaught Error: Call to a member function add_cap() on null in /var/www/vhosts/party.coop/httpdocs/wp-content/plugins/wpfront-user-role-editor/classes/class-wpfront-user-role-editor.php:651
Stack trace:
#0 /var/www/vhosts/party.coop/httpdocs/wp-content/plugins/wpfront-user-role-editor/classes/class-wpfront-user-role-editor.php(219): WPFront_User_Role_Editor->rename_role_capabilities()
#1 /var/www/vhosts/party.coop/httpdocs/wp-includes/class-wp-hook.php(286): WPFront_User_Role_Editor->admin_init(”)
#2 /var/www/vhosts/party.coop/httpdocs/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array)
#3 /var/www/vhosts/party.coop/httpdocs/wp-includes/plugin.php(453): WP_Hook->do_action(Array)
#4 /var/www/vhosts/party.coop/httpdocs/wp-admin/admin-ajax.php(44): do_action(‘admin_init’)
#5 {main}
thrown in /var/www/vhosts/party.coop/httpdocs/wp-content/plugins/wpfront-user-role-editor/classes/class-wpfront-user-role-editor.php on line 651