I would like to loop from a given date through all the days until the current date, but not including the current date.

Piecing together code that I found on the Internet, I came up with the following solution, which does almost what I want:

$date_begin = new DateTime("2005-03-11");
$today = new DateTime("now");
for ($i = $date_begin; $i <= $today; $i->modify("+1 day")) {
...
}

This code loops through all the days from the given date until the current date, including the current date. In order to exclude the current date, I would have thought that I merely need to replace $i <= $today by $i < $today. But this does not work. Even with < instead of <=, the current date is included in the loop. Why is that? What am I misunderstanding? And how can I exclude the current date?