What steps should be taken when upgrading from PHP version 5.3 to 5.4?

When upgrading from PHP version 5.3 to 5.4, it is important to review the PHP migration guide to identify any backward incompatible changes. Some common steps to take include updating deprecated functions, ensuring compatibility with the new syntax, and testing the code thoroughly before deployment.

// Example of upgrading code from PHP 5.3 to 5.4
// Before upgrade
$old_array = array(1, 2, 3);
// After upgrade
$new_array = [1, 2, 3];