Database Error: The PHP `ext/mysql` extension is removed in PHP 7, cannot use the `mysql` driver. Also, this system does not support MySQLi or PDO MySQL. Cannot instantiate database driver. (2 replies)

I've manually installed another PHP version to Wamp. Now I get this message:

Database Error: The PHP `ext/mysql` extension is removed in PHP 7, cannot use the `mysql` driver. Also, this system does not support MySQLi or PDO MySQL. Cannot instantiate database driver.

other php versions work fine.

What do I need to do to get this working again?

Wamp 3.0.4
windows 10
php 7.1.5