Website getting errors trying to upgraded to php 8

Fatal error: Uncaught Error: Call to undefined function mysql_connect() in /home/shrineki/public_html/wp-includes/wp-db.php:1688 Stack trace: #0 /home/shrineki/public_html/wp-includes/wp-db.php(632): wpdb->db_connect() #1 /home/shrineki/public_html/wp-includes/load.php(558): wpdb->__construct(‘shrineki_shrine’, ‘v0295PI!S)’, ‘shrineki_shrine’, ‘localhost’) #2 /home/shrineki/public_html/wp-settings.php(124): require_wp_db() #3 /home/shrineki/public_html/wp-config.php(98): require_once(‘/home/shrineki/…’) #4 /home/shrineki/public_html/wp-load.php(50): require_once(‘/home/shrineki/…’) #5 /home/shrineki/public_html/wp-blog-header.php(13): require_once(‘/home/shrineki/…’) #6 /home/shrineki/public_html/index.php(17): require(‘/home/shrineki/…’) #7 {main} thrown in /home/shrineki/public_html/wp-includes/wp-db.php on line 1688

I have to roll back to php 7.4