Erro after update | WordPress.org

After update my site went down. After deactivate the plugin by ftp the site was fine again. Now i downgraded to the old version.
This is the error i see in the logfile

[12-Sep-2022 08:05:25 UTC] PHP Parse error: syntax error, unexpected ‘=>’ (T_DOUBLE_ARROW), expecting ‘]’ in /wp-content/plugins/age-gate/src/Routes/Rest/Media.php on line 35

This is line 35
‘permission_callback’ => fn () => get_current_user_id() > 0 && current_user_can(Constants::APPEARANCE)