Migrating from PHP 3 to PHP 4
PHP Manual

Cookies

PHP 3 had the bad habit of setting cookies in the reverse order of the setcookie() calls in your code. PHP 4 breaks with this habit and creates the cookie header lines in exactly the same order as you set the cookies in the code.

This might break some existing code, but the old behaviour was so strange to understand that it deserved a change to prevent further problems in the future.


Migrating from PHP 3 to PHP 4
PHP Manual