What are some best practices for migrating PHP code to use preg_replace_callback instead of the /e modifier?

When migrating PHP code to use preg_replace_callback instead of the /e modifier, it is important to understand that the /e modifier is deprecated and poses security risks due to the potential execution of arbitrary PHP code. To solve this issue, replace the /e modifier with preg_replace_callback, which allows you to specify a callback function to process the replacement.

// Original code using /e modifier
$replaced = preg_replace('/pattern/e', 'replacement', $string);

// Updated code using preg_replace_callback
$replaced = preg_replace_callback('/pattern/', function($matches) {
    return 'replacement';
}, $string);