flight.content_length need to be false by default.

[joanhey]

That work is for the webserver.

Check a normal php:

<?php
echo "Hello world!";

Nowhere create the header for the content lenght.

[n0nag0n]

So I hear you, but this can be a v4 project. I could include this in v3, I would just have to document it. The purpose of the v2->v3 upgrade was so that existing project could be upgraded in place without any catastrophic changes. Not that this would be catastrophic, but in the last year or so of working with flight, I've had some projects with some issues with it....... I'd have to think through the consequences and how to make as easy for people to not have problems in their projects.