PHP源码修改：
打开 phpcms\modules\wap\index.php 文件
找到

if(!$r || $r['status'] != 99) showmessage(L('info_does_not_exists'),'blank');

在其下面添加

//上一篇
$previous_page = $this->db->get_one("`catid` = '$catid' AND `id`<'$id' AND `status`=99",'*','id DESC');
//下一篇
$next_page = $this->db->get_one("`catid`= '$catid' AND `id`>'$id' AND `status`=99");
//当前页为第一篇时：再点击上一篇仍然显示第一篇
if(empty($previous_page)) {
$previous_page = $this->db->get_one("`catid` = '$catid' AND `id`='$id' AND `status`=99",'*','id DESC');
}
//当前页为最后一篇时：再点击下一篇仍然显示最后一篇
if(empty($next_page)) {
$next_page = $this->db->get_one("`catid`= '$catid' AND `id`='$id' AND `status`=99");
}

使用排序的上一篇下一篇解决办法

$listorder = $r['listorder'];
//上一篇
$previous_page = $this->db->get_one("`catid` = '$catid' AND `listorder`<'$listorder' AND `status`=99",'*','listorder desc');
//下一篇
$next_page = $this->db->get_one("`catid`= '$catid' AND `listorder`>'$listorder' AND `status`=99",'*','listorder asc');
//当前页为第一篇时：再点击上一篇仍然显示第一篇
if(empty($previous_page)) {
$previous_page = $this->db->get_one("`catid` = '$catid' AND `listorder`='$listorder' AND `status`=99",'*','listorder desc');
}
//当前页为最后一篇时：再点击下一篇仍然显示最后一篇
if(empty($next_page)) {
$next_page = $this->db->get_one("`catid`= '$catid' AND `listorder`='$listorder' AND `status`=99",'*','listorder asc');
}

模板调用：

<a href="{WAP_SITEURL}&a=show&catid={$catid}&typeid=1&id= {$previous_page[id]}">上一篇：{$previous_page[title]}</a>

<a href="{WAP_SITEURL}&a=show&catid={$catid}&typeid=1&id= {$next_page[id]}">上一篇：{$next_page[title]}</a>