How could I change(modify) the correct php version on Debian 9

Hi all,

I have a wordpress on debian 9.

Recently I've updated the php from php7.0 to php7.3 by the command of this page https://www.linode.com/community/questions/19253/how-to-update-php-to-73-for-wordpress-one-click-app-and-debian-9

The result like below:

chenyp@li1690-38:~$ php --version
PHP 7.3.27-2+0~20210213.78+debian9~1.gbpc9cf23 (cli) (built: Feb  13 2021 08:05:53) ( NTS )
Copyright (c) 1997-2018 The PHP Group Zend Engine v3.3.27, Copyright (c) 1998-2018 Zend Technologies with Zend OPcache v7.3.27-2+0~20210213.78+debian9~1.gbpc9cf23, Copyright (c) 1999-2018, by Zend Technologies

It seems that I've updated php successfully.

But.
But.

It still shows the old version of php(7.0) on the control panel of wordpress.

Running PHP version: 7.0.33-40+0~20210213.48+debian9~1.gbpc26c46

Does anyone could help me to figure out the problem?

Thanks.