In PHP programming, what are the drawbacks of modifying code in an existing framework rather than using it as intended?

Modifying code in an existing framework can lead to compatibility issues, maintenance difficulties, and potential conflicts with future updates. It is recommended to extend the functionality of the framework through its provided extension points or by creating custom modules/plugins to maintain the integrity of the framework.

// Example of extending functionality in a framework using a custom module

// CustomModule.php
class CustomModule {
    public function customFunction() {
        // Custom functionality here
    }
}

// index.php
require_once 'CustomModule.php';

$customModule = new CustomModule();
$customModule->customFunction();