1、在任意hook文件夹新建一个 thread_message_after.htm 文件，如下代码。

<?php
if (isset($route) && $route == 'thread') {
    $uid = isset($uid) ? $uid : 0;
    $thread = isset($thread) ? $thread : [];
    $user = isset($user) ? $user : [];
    
    $has_replied = false;
    if ($uid && isset($thread['tid'])) {
        $has_replied = db_count('post', ['uid' => $uid, 'tid' => $thread['tid']]);
    }
    
    $is_admin = isset($user['gid']) && $user['gid'] == 1; 
    if (!$is_admin && !$has_replied && isset($thread['uid']) && ($thread['uid'] != $uid) && isset($thread['files']) && $thread['files'] > 0) { ?>
        <fieldset class="fieldset mt-2 m-0">
            <legend>本帖中包含附件</legend>
            <i class="icon-bell"></i> 附件为<span class="text-danger">回复后可见</span>，请先回复！
        </fieldset>
    <?php } else { ?>

2、再新建一个文件 thread_filelist_after.htm 放以下代码（包裹附件框）