What are the potential consequences of using deprecated functions in PHP?

Using deprecated functions in PHP can lead to compatibility issues with newer versions of PHP, as these functions may be removed in future releases. This can result in broken functionality or security vulnerabilities in your code. To solve this issue, you should update your code to use the recommended alternatives to deprecated functions.

// Deprecated function
$old_result = mysql_query($query);

// Updated code using mysqli functions
$connection = mysqli_connect($host, $username, $password, $database);
$new_result = mysqli_query($connection, $query);