WordPress and PHP 7.1

I’m having a problem with PHP 7.1.11 and WordPress 4.8.3 using nginx on a windows machine, everytime I get the error below:

2017/11/03 20:22:24 [error] 6016#6060: *3 FastCGI sent in stderr: “PHP Fatal error: Uncaught Error: Call to undefined function mysql_connect() in C:\Sites\meustostoes\wp-includes\wp-db.php:1635
Stack trace:
#0 C:\Sites\meustostoes\wp-includes\wp-db.php(658): wpdb->db_connect()
#1 C:\Sites\meustostoes\wp-includes\load.php(404): wpdb->__construct(‘root’, ‘mysql’, ‘meustostoes’, ‘localhost’)
#2 C:\Sites\meustostoes\wp-settings.php(106): require_wp_db()
#3 C:\Sites\meustostoes\wp-config.php(91): require_once(‘C:\\Sites\\meusto…’)
#4 C:\Sites\meustostoes\wp-load.php(37): require_once(‘C:\\Sites\\meusto…’)
#5 C:\Sites\meustostoes\wp-blog-header.php(13): require_once(‘C:\\Sites\\meusto…’)
#6 C:\Sites\meustostoes\index.php(17): require(‘C:\\Sites\\meusto…’)
#7 C:\Users\joel_\AppData\Roaming\Composer\vendor\cretueusebiu\valet-windows\server.php(132): require(‘C:\\Sites\\meusto…’)
#8 {main}
thrown in C:\Sites\meustostoes\wp-includes\wp-db.php on line 1635” while reading response header from upstream, client: 127.0.0.1, server: , request: “GET / HTTP/1.1”, upstream: “fastcgi://127.0.0.1:9000”, host: “meustostoes.app”

mysqli is enabled on my php installation and everything seems to be all right, what can I do to solve this!? o.O