That's not an error, that's a deprecated message (for each() since PHP 7.2.0), means the function will cease to exist in a later PHP version (here PHP 8.0.0). Means the AStat plugin will break then.

You can suppress the "Deprecated" messages by setting
$conf['show_php_errors'] = E_ALL & ~E_DEPRECATED;
in your local config.

Or better do all logging to file, see [Forum, post 180778 by erAck in topic 31258] Error Message.