Updating PHP to 7.4.6 Fatal error (no replies)

Hello,

I am trying to update my WampServer 3.1.4 64bit with the latest version of PHP 7.4.6 but I must have missed a step as I am getting a fatal error when trying to view any of the sites.

I have created a folder in Wamp64/bin/php called php7.4.6

I've then downloaded version 7.4.6 and extracted contents to my new folder.

I've copied over three files to this folder from version 7.2.10

php.ini
PhpForApache
wamp.conf

I've edited the php.ini at line 741 to read extension_dir ="c:/wamp64/bin/php/php7.4.6/ext/"

When restarting Wamp I can select version 7.4.6 and PHP restarts successfully.

However, when I try to view any sites, I get a fatal error like the following-

Fatal error: Uncaught Error: Call to undefined function mysql_connect() in C:\wamp64\www\finaltouchglobal\wp-includes\wp-db.php:1661 Stack trace: #0 C:\wamp64\www\finaltouchglobal\wp-includes\wp-db.php(631): wpdb->db_connect() #1 C:\wamp64\www\finaltouchglobal\wp-includes\load.php(426): wpdb->__construct('root', '', 'ftg', 'localhost') #2 C:\wamp64\www\finaltouchglobal\wp-settings.php(126): require_wp_db() #3 C:\wamp64\www\finaltouchglobal\wp-config.php(90): require_once('C:\\wamp64\\www\\f...') #4 C:\wamp64\www\finaltouchglobal\wp-load.php(37): require_once('C:\\wamp64\\www\\f...') #5 C:\wamp64\www\finaltouchglobal\wp-blog-header.php(13): require_once('C:\\wamp64\\www\\f...') #6 C:\wamp64\www\finaltouchglobal\index.php(17): require('C:\\wamp64\\www\\f...') #7 {main} thrown in C:\wamp64\www\finaltouchglobal\wp-includes\wp-db.php on line 1661

There has been a critical error on your website.

It looks like some sort of database issue, but I'm a bit lost on how to fix it.

If anyone can advise, it would be much appreciated.

Myles