When you upgrade from PHP 5.6 to PHP 7.3, you will be faced unexpected stopping on your PHP code in case of following case.
Missing ereg_
For example, ereg_replace can be replaced by preg_replace like below:
$pre_name = preg_replace( "/http(.*).com\//", "", $url);
$pre_name = preg_replace( "/\//", "_", $pre_name);
$pre_name = preg_replace( "/\?(.*)/", "", $pre_name);
$pre_name = preg_replace( "/.php(.*)/", "", $pre_name) . "_" . str_replace(":", "", $scheduled_time);
Missing mysql_
All of mysql_ function is gone.