In what ways can upgrading to a newer version of PHP, such as PHP 5.3 or higher, improve the security and stability of an online shop application?

Upgrading to a newer version of PHP, such as PHP 5.3 or higher, can improve the security and stability of an online shop application by providing access to the latest security patches and features. Older versions of PHP may have vulnerabilities that can be exploited by attackers, putting the application and its users at risk. By keeping PHP up to date, developers can ensure that their application is better protected against potential security threats.

// Code snippet to check PHP version and display a warning if it is outdated
if (version_compare(PHP_VERSION, '5.3.0') < 0) {
    echo "Warning: Your PHP version is outdated. Please upgrade to a newer version for improved security and stability.";
}