What potential pitfalls should PHP developers be aware of when updating to PHP 8, such as the deactivation of mb_substr()?

When updating to PHP 8, PHP developers should be aware that the mb_substr() function has been removed and deprecated. Instead, developers should use the mb_strcut() function as a replacement for mb_substr(). This change ensures compatibility with PHP 8 and prevents any potential issues with code that relies on mb_substr().

// Replace mb_substr() with mb_strcut()
$substring = mb_strcut($string, $start, $length);