How can developers ensure their PHP code is updated to avoid deprecated functions and warnings?

To ensure PHP code is updated to avoid deprecated functions and warnings, developers should regularly review their codebase for deprecated functions and replace them with updated alternatives. They should also stay informed about PHP updates and changes to avoid using deprecated features in the first place. Using tools like PHP CodeSniffer can help identify deprecated functions in the codebase.

// Example of replacing a deprecated function with an updated alternative
// Deprecated function: mysql_query()
// Updated alternative: mysqli_query()

// Deprecated code
$result = mysql_query($query);

// Updated code
$conn = mysqli_connect($host, $username, $password, $database);
$result = mysqli_query($conn, $query);