我从https://www.stata.com/support/updates/stata15.html下载了升级包 stata15update_mac.zip，按照官网提示，解压升级。

Type "db update" in Stata and browse to the extracted update directory. Click OK and follow any instructions you are given.

但是没有成功。不知道啥原因。请高手指点，谢谢！！
命令和提示如下：

. db update
. update all, from("/Users/xrs/Downloads/stata15update_mac.")
(examining /Users/xrs/Downloads/stata15update_mac.)
file /Users/xrs/Downloads/stata15update_mac./stata.upd not found
/Users/xrs/Downloads/stata15update_mac. is not a valid update disk
r(601);