What are the risks of using outdated PHP codes in terms of security vulnerabilities and performance issues?

Using outdated PHP codes can expose your application to security vulnerabilities such as SQL injection, cross-site scripting, and remote code execution. Additionally, outdated PHP codes may also lead to performance issues due to deprecated functions and inefficient coding practices. To mitigate these risks, it is important to regularly update your PHP version and refactor outdated code to adhere to the latest best practices and security standards.

// Example of updating outdated code to prevent SQL injection vulnerability
$unsafe_variable = $_POST['user_input'];
$safe_variable = mysqli_real_escape_string($connection, $unsafe_variable);

// Use prepared statements to prevent SQL injection
$stmt = $connection->prepare("SELECT * FROM users WHERE username = ?");
$stmt->bind_param("s", $safe_variable);
$stmt->execute();
$result = $stmt->get_result();