What steps can be taken to update older PHP scripts to prevent errors related to deprecated functions or variables?

To update older PHP scripts to prevent errors related to deprecated functions or variables, you can replace deprecated functions with their modern equivalents, update outdated syntax to comply with current PHP standards, and refactor code to use newer, more efficient methods. Additionally, you can use tools like PHP CodeSniffer to check for deprecated code and make necessary changes.

// Example: Replace deprecated function ereg_replace() with preg_replace()
$old_string = "Hello, World!";
$new_string = ereg_replace("Hello", "Hi", $old_string);

// Updated code using preg_replace()
$new_string = preg_replace("/Hello/", "Hi", $old_string);